user: You are a structured reasoning expert tasked with solving problems step by step. 
You first think about the reasoning process in the mind and then provide the answer. The reasoning process and answer should be enclosed within <think> </think> and <answer> </answer> tags, respectively, i.e., <think> reasoning process here </think> <answer> answer here </answer>. 
Given a question and the associated knowledge graph triplets (entity, relation, entity), you are asked to answer the question with these triplets and your own knowledge. 
You can break down the original question into several sub-questions and explore the given knowledge graph to solve them step-by-step. If there are multiple possible answers, choose one as the final answer. 
After thinking, when you finally reach a conclusion, clearly state the answer within <answer> </answer> tags, i.e., <answer> answer here </answer>. 
Question: what is the unit of mass in the measurement system that uses gray per second? 
Knowledge Triplets: Siemens per meter, measurement_unit.unit_of_conductivity.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.absorbed_dose_rate_units, Gray per second
Kilobit per second, measurement_unit.unit_of_data_transmission_rate.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.molar_volume_units, Cubic metre per mole
International System of Units, measurement_unit.measurement_system.catalytic_activity_units, Katal
International System of Units, measurement_unit.measurement_system.temperature_units, Degree Celsius
International System of Units, measurement_unit.measurement_system.time_units, zeptosecond
International System of Units, measurement_unit.measurement_system.time_units, Femtosecond
Terabit per second, measurement_unit.unit_of_data_transmission_rate.measurement_system, International System of Units
Ampere, measurement_unit.current_unit.measurement_system, International System of Units
Rate in grays per second, type.object.permission, m.014_
yoctosecond, measurement_unit.time_unit.measurement_system, International System of Units
Gray, measurement_unit.absorbed_dose_unit.measurement_system, International System of Units
International System of Units, measurement_unit.mass_unit.measurement_system, Microgram
International System of Units, measurement_unit.measurement_system.exposure_units, Coulomb per kilogram
International System of Units, measurement_unit.measurement_system.volume_units, Hectoliter
Kilojoule per mole, measurement_unit.molar_energy_unit.measurement_system, International System of Units
Centisecond, measurement_unit.time_unit.measurement_system, International System of Units
Gigapascal, measurement_unit.pressure_unit.measurement_system, International System of Units
Micrometer, measurement_unit.distance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.mass_unit.measurement_system, Gram
International System of Units, measurement_unit.measurement_system.time_units, Attosecond
Cubic metre per second, measurement_unit.unit_of_volumetric_flow_rate.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.catalytic_concentration_units, Katal per cubic metre
Pascal, measurement_unit.pressure_unit.measurement_system, International System of Units
Second, measurement_unit.time_unit.measurement_system, International System of Units
Meter, measurement_unit.distance_unit.measurement_system, International System of Units
Coulomb per square metre, measurement_unit.electric_flux_density_unit.measurement_system, International System of Units
Inverse Kelvin, measurement_unit.inverse_temperature_unit.measurement_system, International System of Units
Watt per square metre per steradian, measurement_unit.radiance_unit.measurement_system, International System of Units
Coulomb, measurement_unit.charge_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.length_units, Picometre
International System of Units, measurement_unit.measurement_system.volume_units, Cubic kilometer
International System of Units, measurement_unit.measurement_system.volume_units, Deciliter
Cubic metre, measurement_unit.volume_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.molar_heat_capacity_units, Joule per mole per kelvin
Rate in grays per second, type.property.expected_type, Floating Point Number
International System of Units, measurement_unit.measurement_system.weight_units, Gram
International System of Units, measurement_unit.measurement_system.acceleration_units, Metre per second squared
International System of Units, measurement_unit.measurement_system.molar_energy_units, Joule per mole
Reciprocal metre, measurement_unit.wavenumber_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.specific_volume_units, Cubic metre per kilogram
International System of Units, measurement_unit.measurement_system.time_units, Gigasecond
International System of Units, measurement_unit.measurement_system.specific_energy_units, Joule per gram
International System of Units, measurement_unit.measurement_system.time_units, hectosecond
International System of Units, measurement_unit.measurement_system.illuminance_units, Lux
m.014_, type.permission.controls, Rate in grays per second
Megawatt, measurement_unit.power_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.length_units, Decametre
Ohm centimeter, measurement_unit.unit_of_resistivity.measurement_system, International System of Units
Kilometres per hour, measurement_unit.speed_unit.measurement_system, International System of Units
Joule per cubic metre per kelvin, measurement_unit.volumetric_heat_capacity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.thermal_conductivity_units, Watt per meter per kelvin
Nanomolar, measurement_unit.amount_concentration_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.volume_units, Milliliter
Watt per meter per kelvin, measurement_unit.thermal_conductivity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.resistivity_units, Ohm centimeter
Joule, measurement_unit.energy_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.power_units, Kilowatt
International System of Units, measurement_unit.measurement_system.force_moment_units, Newton metre
International System of Units, measurement_unit.measurement_system.specific_heat_capacity_units, Joule per kilogram per kelvin
International System of Units, measurement_unit.measurement_system.energy_units, Kilojoule
International System of Units, measurement_unit.measurement_system.luminous_flux_units, Lumen
Ampere per metre, measurement_unit.magnetic_field_strength_unit.measurement_system, International System of Units
Milligram, measurement_unit.mass_unit.measurement_system, International System of Units
Milliwatt, measurement_unit.power_unit.measurement_system, International System of Units
Kilogram per square metre, measurement_unit.unit_of_surface_density.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.energy_density_units, Joule per cubic metre
Volt, measurement_unit.potential_unit.measurement_system, International System of Units
Rate in grays per second, type.property.unit, Gray per second
Deciliter, measurement_unit.volume_unit.measurement_system, International System of Units
International System of Units, measurement_unit.mass_unit.measurement_system, Kilogram
Hectometre, measurement_unit.distance_unit.measurement_system, International System of Units
Gray per second, measurement_unit.absorbed_dose_rate_unit.measurement_system, International System of Units
bit per second, measurement_unit.unit_of_data_transmission_rate.measurement_system, International System of Units
Newton per metre, measurement_unit.surface_tension_unit.measurement_system, International System of Units
Femtosecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.viscosity_units, Pascal second
International System of Units, measurement_unit.measurement_system.magnetic_flux_density_units, Tesla
Unit of Absorbed Dose Rate, type.type.properties, Rate in grays per second
m.0qrbg_1, dataworld.gardening_hint.last_referenced_by, International System of Units
Watt per square metre, measurement_unit.irradiance_unit.measurement_system, International System of Units
Mole, measurement_unit.substance_unit.measurement_system, International System of Units
micro per degree C, measurement_unit.inverse_temperature_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.weight_units, Tonne
Volt per metre, measurement_unit.electric_field_strength_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.power_units, Watt
Joule per gram per kelvin, measurement_unit.specific_heat_capacity_unit.measurement_system, International System of Units
Watt per steradian, measurement_unit.radiant_intensity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.inverse_temperature_units, micro per degree C
International System of Units, measurement_unit.measurement_system.pressure_units, Gigapascal
Joule per gram, measurement_unit.specific_energy_unit.measurement_system, International System of Units
Joule per mole, measurement_unit.molar_energy_unit.measurement_system, International System of Units
Megametre, measurement_unit.distance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.data_rate_units, Gigabit per second
Becquerel, measurement_unit.radioactivity_unit.measurement_system, International System of Units
Centiliter, measurement_unit.volume_unit.measurement_system, International System of Units
Radian per second squared, measurement_unit.angular_acceleration_unit.measurement_system, International System of Units
Farad, measurement_unit.capacitance_unit.measurement_system, International System of Units
Sievert, measurement_unit.dose_equivalence_unit.measurement_system, International System of Units
Attosecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, Megasecond
Kilosecond, measurement_unit.time_unit.measurement_system, International System of Units
Cubic kilometer, measurement_unit.volume_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.volumetric_heat_capacity_units, Joule per cubic metre per kelvin
Tonne, measurement_unit.mass_unit.measurement_system, International System of Units
Millisecond, measurement_unit.time_unit.measurement_system, International System of Units
Gram, measurement_unit.mass_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, Microsecond
International System of Units, measurement_unit.measurement_system.data_rate_units, Megabit per second
International System of Units, measurement_unit.measurement_system.frequency_units, Megahertz
Square kilometer, measurement_unit.area_unit.measurement_system, International System of Units
terasecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, Picosecond
Millisiemens, measurement_unit.conductance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.angle_units, Radian
Henry per metre, measurement_unit.permeability_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.magnetic_flux_units, Weber
International System of Units, measurement_unit.measurement_system.frequency_units, Gigahertz
decisecond, measurement_unit.time_unit.measurement_system, International System of Units
Metre per second squared, measurement_unit.acceleration_unit.measurement_system, International System of Units
Candela per square metre, measurement_unit.luminance_unit.measurement_system, International System of Units
Molar, measurement_unit.amount_concentration_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, exasecond
Kilogram per cubic metre, measurement_unit.unit_of_density.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.surface_density_units, Kilogram per square metre
International System of Units, measurement_unit.measurement_system.conductance_units, Millisiemens
International System of Units, base.schemastaging.context_name.pronunciation, g.125_p8yyr
International System of Units, measurement_unit.measurement_system.length_units, Nanometre
International System of Units, measurement_unit.measurement_system.time_units, zettasecond
International System of Units, measurement_unit.measurement_system.pressure_units, Pascal
International System of Units, measurement_unit.measurement_system.length_units, Hectometre
International System of Units, measurement_unit.measurement_system.weight_units, Microgram
International System of Units, measurement_unit.mass_unit.measurement_system, Tonne
International System of Units, measurement_unit.measurement_system.permittivity_units, Farad per metre
International System of Units, measurement_unit.measurement_system.radioactivity_units, Becquerel
Hectoliter, measurement_unit.volume_unit.measurement_system, International System of Units
Kilogram, measurement_unit.mass_unit.measurement_system, International System of Units
Newton metre, measurement_unit.force_moment_unit.measurement_system, International System of Units
Farad per metre, measurement_unit.permittivity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, Nanosecond
Kelvin, measurement_unit.temperature_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.weight_units, Kilogram
Lumen, measurement_unit.luminous_flux_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.potential_units, Volt
Decametre, measurement_unit.distance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.power_units, Milliwatt
International System of Units, measurement_unit.measurement_system.amount_concentration_units, Mole per cubic metre
Gigasecond, measurement_unit.time_unit.measurement_system, International System of Units
Steradian, measurement_unit.solid_angle_unit.measurement_system, International System of Units
hectosecond, measurement_unit.time_unit.measurement_system, International System of Units
Rate in grays per second, type.property.schema, Unit of Absorbed Dose Rate
International System of Units, measurement_unit.measurement_system.time_units, decisecond
Estelle, base.yupgrade.user.topics, International System of Units
International System of Units, measurement_unit.measurement_system.length_units, Megametre
Ampere per square metre, measurement_unit.current_density_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.length_units, Decimetre
Radian per second, measurement_unit.angular_velocity_unit.measurement_system, International System of Units
Rate in grays per second, type.property.unique, true
International System of Units, measurement_unit.measurement_system.magnetic_field_strength_units, Ampere per metre
International System of Units, measurement_unit.measurement_system.temperature_units, Kelvin
International System of Units, measurement_unit.measurement_system.luminance_units, Candela per square metre
Coulomb per kilogram, measurement_unit.exposure_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.resistivity_units, Ohm meter
International System of Units, measurement_unit.measurement_system.absorbed_dose_units, Gray
International System of Units, measurement_unit.measurement_system.speed_units, Kilometres per hour
International System of Units, measurement_unit.measurement_system.time_units, Second
Joule per mole per kelvin, measurement_unit.molar_heat_capacity_unit.measurement_system, International System of Units
Milliliter, measurement_unit.volume_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.surface_tension_units, Newton per metre
Gigabit per second, measurement_unit.unit_of_data_transmission_rate.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.data_rate_units, Terabit per second
International System of Units, measurement_unit.measurement_system.current_units, Ampere
Mole per cubic metre, measurement_unit.amount_concentration_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.charge_units, Coulomb
International System of Units, measurement_unit.measurement_system.power_units, Megawatt
Picometre, measurement_unit.distance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, yottasecond
International System of Units, measurement_unit.measurement_system.irradiance_units, Watt per square metre
Lux, measurement_unit.illuminance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.length_units, Kilometer
Coulomb per cubic metre, measurement_unit.electric_charge_density_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.area_units, Square meter
International System of Units, measurement_unit.measurement_system.angular_velocity_units, Radian per second
International System of Units, measurement_unit.measurement_system.time_units, Kilosecond
Kilometer, measurement_unit.distance_unit.measurement_system, International System of Units
Millimeter, measurement_unit.distance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.force_units, Newton
Microgram, measurement_unit.mass_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.amount_concentration_units, Nanomolar
Microsiemens per centimeter, measurement_unit.unit_of_conductivity.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.wavenumber_units, Reciprocal metre
petasecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.speed_units, Kilometres per second
decasecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.specific_heat_capacity_units, Joule per gram per kelvin
International System of Units, measurement_unit.measurement_system.electric_charge_density_units, Coulomb per cubic metre
International System of Units, measurement_unit.measurement_system.conductance_units, Siemens
Kilometres per second, measurement_unit.speed_unit.measurement_system, International System of Units
exasecond, measurement_unit.time_unit.measurement_system, International System of Units
Henry, measurement_unit.inductance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, Millisecond
International System of Units, measurement_unit.measurement_system.density_units, Kilogram per cubic metre
International System of Units, measurement_unit.measurement_system.heat_capacity_units, Joule per kelvin
International System of Units, measurement_unit.measurement_system.inductance_units, Henry
Liter, measurement_unit.volume_unit.measurement_system, International System of Units
Ohm, measurement_unit.resistance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.inverse_temperature_units, Inverse Kelvin
International System of Units, measurement_unit.measurement_system.specific_energy_units, Joule per kilogram
Radian, measurement_unit.angle_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.substance_units, Mole
Megahertz, measurement_unit.unit_of_frequency.measurement_system, International System of Units
Square meter, measurement_unit.area_unit.measurement_system, International System of Units
Joule per kelvin, measurement_unit.heat_capacity_unit.measurement_system, International System of Units
Newton, measurement_unit.unit_of_force.measurement_system, International System of Units
Kilojoule, measurement_unit.energy_unit.measurement_system, International System of Units
Weber, measurement_unit.magnetic_flux_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.frequency_units, Hertz
Katal per cubic metre, measurement_unit.catalytic_concentration_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.current_density_units, Ampere per square metre
Gray per second, measurement_unit.absorbed_dose_rate_unit.rate_in_grays_per_second, 1.0
zettasecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.volume_units, Liter
Gigahertz, measurement_unit.unit_of_frequency.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.electric_flux_density_units, Coulomb per square metre
International System of Units, measurement_unit.measurement_system.frequency_units, Kilohertz
International System of Units, measurement_unit.measurement_system.amount_concentration_units, Micromolar
International System of Units, measurement_unit.measurement_system.length_units, Centimeter
International System of Units, measurement_unit.measurement_system.amount_concentration_units, Molar
Cubic metre per mole, measurement_unit.molar_volume_unit.measurement_system, International System of Units
Picosecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.luminous_intensity_units, Candela
International System of Units, measurement_unit.measurement_system.length_units, Micrometer
International System of Units, measurement_unit.measurement_system.energy_units, Joule
International System of Units, measurement_unit.measurement_system.pressure_units, Kilopascal
Ohm meter, measurement_unit.unit_of_resistivity.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.capacitance_units, Farad
Kilowatt, measurement_unit.power_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.volume_units, Centiliter
International System of Units, measurement_unit.measurement_system.data_rate_units, bit per second
Metre per second, measurement_unit.speed_unit.measurement_system, International System of Units
Absorbed dose rate, measurement_unit.dimension.units, Gray per second
International System of Units, measurement_unit.mass_unit.measurement_system, Milligram
International System of Units, measurement_unit.measurement_system.speed_units, Metre per second
Siemens, measurement_unit.conductance_unit.measurement_system, International System of Units
Degree Celsius, measurement_unit.temperature_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.length_units, Millimeter
International System of Units, measurement_unit.measurement_system.volume_units, Cubic metre
Candela, measurement_unit.luminous_intensity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.resistance_units, Ohm
Tesla, measurement_unit.magnetic_flux_density_unit.measurement_system, International System of Units
yottasecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.molar_energy_units, Kilojoule per mole
Joule per cubic metre, measurement_unit.energy_density_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.length_units, Meter
Kilohertz, measurement_unit.unit_of_frequency.measurement_system, International System of Units
Kilopascal, measurement_unit.pressure_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.data_rate_units, Kilobit per second
International System of Units, measurement_unit.measurement_system.dose_equivalence_units, Sievert
Microsiemens, measurement_unit.conductance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.radiance_units, Watt per square metre per steradian
Nanosecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, petasecond
International System of Units, measurement_unit.measurement_system.electric_field_strength_units, Volt per metre
International System of Units, measurement_unit.measurement_system.radiant_intensity_units, Watt per steradian
Cubic metre per kilogram, measurement_unit.specific_volume_unit.measurement_system, International System of Units
Microsecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.conductance_units, Microsiemens
Decimetre, measurement_unit.distance_unit.measurement_system, International System of Units
Micromolar, measurement_unit.amount_concentration_unit.measurement_system, International System of Units
Megasecond, measurement_unit.time_unit.measurement_system, International System of Units
Pascal second, measurement_unit.viscosity_unit.measurement_system, International System of Units
Centimeter, measurement_unit.distance_unit.measurement_system, International System of Units
Nanometre, measurement_unit.distance_unit.measurement_system, International System of Units
Katal, measurement_unit.catalytic_activity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.pressure_units, Megapascal
Joule per kilogram, measurement_unit.specific_energy_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, yoctosecond
Hertz, measurement_unit.unit_of_frequency.measurement_system, International System of Units
Megabit per second, measurement_unit.unit_of_data_transmission_rate.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.solid_angle_units, Steradian
International System of Units, measurement_unit.measurement_system.area_units, Square kilometer
International System of Units, measurement_unit.measurement_system.angular_acceleration_units, Radian per second squared
International System of Units, measurement_unit.measurement_system.permeability_units, Henry per metre
International System of Units, measurement_unit.measurement_system.time_units, terasecond
Absorbed dose rate, measurement_unit.dimension.si_base_unit, Gray per second
zeptosecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, decasecond
Joule per kilogram per kelvin, measurement_unit.specific_heat_capacity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.weight_units, Milligram
Watt, measurement_unit.power_unit.measurement_system, International System of Units
Floating Point Number, type.type.expected_by, Rate in grays per second
International System of Units, user.avh.default_domain.ellerdale_topic.ellerdale_id, 0080-5e5f
International System of Units, measurement_unit.measurement_system.volumetric_flow_rate_units, Cubic metre per second
International System of Units, measurement_unit.measurement_system.time_units, Centisecond
Megapascal, measurement_unit.pressure_unit.measurement_system, International System of Units

Answer: Tonne
Kilogram
Milligram
Gram
Microgram