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: watt per square metre per steradian is the electric field strength unit of which measurement system? 
Knowledge Triplets: Radiance in watts per square meter per steradian, type.property.expected_type, Floating Point Number
International System of Units, measurement_unit.measurement_system.exposure_units, Coulomb per kilogram
Mole per cubic metre, measurement_unit.amount_concentration_unit.measurement_system, International System of Units
zettasecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, decasecond
Molar, measurement_unit.amount_concentration_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.time_units, Megasecond
Kilowatt, measurement_unit.power_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.wavenumber_units, Reciprocal metre
Centiliter, measurement_unit.volume_unit.measurement_system, International System of Units
Watt per square metre per steradian, measurement_unit.radiance_unit.radiance_in_watts_per_square_meter_per_steradian, 1.0
Joule per mole per kelvin, measurement_unit.molar_heat_capacity_unit.measurement_system, International System of Units
Coulomb per kilogram, measurement_unit.exposure_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.catalytic_concentration_units, Katal per cubic metre
International System of Units, measurement_unit.measurement_system.pressure_units, Kilopascal
International System of Units, measurement_unit.measurement_system.conductance_units, Microsiemens
International System of Units, measurement_unit.measurement_system.electric_flux_density_units, Coulomb per square metre
Tesla, measurement_unit.magnetic_flux_density_unit.measurement_system, International System of Units
hectosecond, measurement_unit.time_unit.measurement_system, International System of Units
Radian, measurement_unit.angle_unit.measurement_system, International System of Units
Siemens per meter, measurement_unit.unit_of_conductivity.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.inverse_temperature_units, micro per degree C
International System of Units, measurement_unit.measurement_system.volume_units, Cubic metre
Gigapascal, measurement_unit.pressure_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, terasecond
Metre per second, measurement_unit.speed_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.data_rate_units, Megabit per second
Kilogram per cubic metre, measurement_unit.unit_of_density.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.luminous_flux_units, Lumen
Micromolar, measurement_unit.amount_concentration_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.conductance_units, Millisiemens
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.speed_units, Kilometres per hour
Joule per cubic metre, measurement_unit.energy_density_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.absorbed_dose_rate_units, Gray per second
International System of Units, measurement_unit.measurement_system.length_units, Meter
International System of Units, measurement_unit.measurement_system.length_units, Nanometre
Joule per kilogram, measurement_unit.specific_energy_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.permittivity_units, Farad per metre
International System of Units, measurement_unit.measurement_system.length_units, Picometre
Kilogram per square metre, measurement_unit.unit_of_surface_density.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.angle_units, Radian
International System of Units, measurement_unit.measurement_system.dose_equivalence_units, Sievert
International System of Units, measurement_unit.measurement_system.molar_volume_units, Cubic metre per mole
International System of Units, measurement_unit.measurement_system.force_moment_units, Newton metre
International System of Units, measurement_unit.measurement_system.absorbed_dose_units, Gray
International System of Units, measurement_unit.measurement_system.catalytic_activity_units, Katal
International System of Units, measurement_unit.measurement_system.specific_volume_units, Cubic metre per kilogram
Farad, measurement_unit.capacitance_unit.measurement_system, International System of Units
Picometre, measurement_unit.distance_unit.measurement_system, International System of Units
Candela per square metre, measurement_unit.luminance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.volume_units, Deciliter
Radian per second squared, measurement_unit.angular_acceleration_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.temperature_units, Degree Celsius
International System of Units, measurement_unit.measurement_system.time_units, Centisecond
International System of Units, measurement_unit.measurement_system.time_units, yottasecond
International System of Units, measurement_unit.measurement_system.time_units, Attosecond
International System of Units, measurement_unit.measurement_system.conductance_units, Siemens
Picosecond, measurement_unit.time_unit.measurement_system, International System of Units
Newton per metre, measurement_unit.surface_tension_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.pressure_units, Pascal
International System of Units, measurement_unit.measurement_system.amount_concentration_units, Molar
International System of Units, measurement_unit.measurement_system.time_units, Nanosecond
International System of Units, measurement_unit.measurement_system.solid_angle_units, Steradian
International System of Units, measurement_unit.measurement_system.volume_units, Centiliter
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.specific_heat_capacity_units, Joule per gram per kelvin
Cubic metre per second, measurement_unit.unit_of_volumetric_flow_rate.measurement_system, International System of Units
Kilosecond, measurement_unit.time_unit.measurement_system, International System of Units
Milligram, measurement_unit.mass_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.resistivity_units, Ohm centimeter
Reciprocal metre, measurement_unit.wavenumber_unit.measurement_system, International System of Units
Henry, measurement_unit.inductance_unit.measurement_system, International System of Units
Cubic metre per kilogram, measurement_unit.specific_volume_unit.measurement_system, International System of Units
Pascal second, measurement_unit.viscosity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.resistance_units, Ohm
International System of Units, measurement_unit.measurement_system.power_units, Megawatt
Centimeter, measurement_unit.distance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, exasecond
International System of Units, measurement_unit.measurement_system.temperature_units, Kelvin
International System of Units, measurement_unit.measurement_system.time_units, hectosecond
Cubic metre, measurement_unit.volume_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.illuminance_units, Lux
Gray, measurement_unit.absorbed_dose_unit.measurement_system, International System of Units
Decimetre, measurement_unit.distance_unit.measurement_system, International System of Units
Joule per gram, measurement_unit.specific_energy_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.molar_energy_units, Joule per mole
International System of Units, measurement_unit.measurement_system.time_units, Millisecond
International System of Units, measurement_unit.measurement_system.radiant_intensity_units, Watt per steradian
International System of Units, measurement_unit.measurement_system.angular_velocity_units, Radian per second
International System of Units, measurement_unit.measurement_system.molar_heat_capacity_units, Joule per mole per kelvin
International System of Units, measurement_unit.measurement_system.inverse_temperature_units, Inverse Kelvin
Millisiemens, measurement_unit.conductance_unit.measurement_system, International System of Units
Femtosecond, measurement_unit.time_unit.measurement_system, International System of Units
Kilohertz, measurement_unit.unit_of_frequency.measurement_system, International System of Units
petasecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, Picosecond
Cubic metre per mole, measurement_unit.molar_volume_unit.measurement_system, International System of Units
zeptosecond, measurement_unit.time_unit.measurement_system, International System of Units
Kilometres per second, measurement_unit.speed_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.length_units, Megametre
International System of Units, measurement_unit.measurement_system.current_density_units, Ampere per square metre
Megahertz, measurement_unit.unit_of_frequency.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.volume_units, Cubic kilometer
International System of Units, measurement_unit.measurement_system.amount_concentration_units, Mole per cubic metre
International System of Units, measurement_unit.measurement_system.charge_units, Coulomb
International System of Units, measurement_unit.measurement_system.frequency_units, Megahertz
Kilometres per hour, measurement_unit.speed_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
Ampere per square metre, measurement_unit.current_density_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.weight_units, Milligram
International System of Units, measurement_unit.measurement_system.data_rate_units, Terabit per second
Kilojoule, measurement_unit.energy_unit.measurement_system, International System of Units
Katal, measurement_unit.catalytic_activity_unit.measurement_system, International System of Units
Deciliter, measurement_unit.volume_unit.measurement_system, International System of Units
Radian per second, measurement_unit.angular_velocity_unit.measurement_system, International System of Units
Hectoliter, measurement_unit.volume_unit.measurement_system, International System of Units
Watt, measurement_unit.power_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.specific_energy_units, Joule per kilogram
Ohm, measurement_unit.resistance_unit.measurement_system, International System of Units
Coulomb per square metre, measurement_unit.electric_flux_density_unit.measurement_system, International System of Units
decisecond, measurement_unit.time_unit.measurement_system, International System of Units
m.0qrbg_1, dataworld.gardening_hint.last_referenced_by, International System of Units
International System of Units, measurement_unit.measurement_system.weight_units, Tonne
International System of Units, measurement_unit.measurement_system.surface_density_units, Kilogram per square metre
terasecond, measurement_unit.time_unit.measurement_system, International System of Units
m.0r394vr, dataworld.gardening_hint.last_referenced_by, Radiance
International System of Units, measurement_unit.measurement_system.thermal_conductivity_units, Watt per meter per kelvin
International System of Units, measurement_unit.measurement_system.time_units, decisecond
m.014_, type.permission.controls, Radiance in watts per square meter per steradian
Estelle, base.yupgrade.user.topics, International System of Units
Ampere per metre, measurement_unit.magnetic_field_strength_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.power_units, Watt
Micrometer, measurement_unit.distance_unit.measurement_system, International System of Units
Watt per square metre, measurement_unit.irradiance_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.irradiance_units, Watt per square metre
bit per second, measurement_unit.unit_of_data_transmission_rate.measurement_system, International System of Units
Coulomb per cubic metre, measurement_unit.electric_charge_density_unit.measurement_system, International System of Units
Gigasecond, measurement_unit.time_unit.measurement_system, International System of Units
Attosecond, measurement_unit.time_unit.measurement_system, International System of Units
Kilojoule per mole, measurement_unit.molar_energy_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.substance_units, Mole
Megametre, measurement_unit.distance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, Femtosecond
International System of Units, measurement_unit.measurement_system.speed_units, Metre per second
International System of Units, measurement_unit.measurement_system.length_units, Kilometer
Ampere, measurement_unit.current_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.speed_units, Kilometres per second
micro per degree C, measurement_unit.inverse_temperature_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.permeability_units, Henry per metre
Milliwatt, measurement_unit.power_unit.measurement_system, International System of Units
Liter, measurement_unit.volume_unit.measurement_system, International System of Units
Radiance in watts per square meter per steradian, type.property.schema, Unit of Radiance
Kilometer, measurement_unit.distance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.surface_tension_units, Newton per metre
International System of Units, measurement_unit.measurement_system.volume_units, Hectoliter
Radiance, measurement_unit.dimension.si_base_unit, Watt per square metre per steradian
International System of Units, measurement_unit.measurement_system.time_units, Second
Joule per kelvin, measurement_unit.heat_capacity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.data_rate_units, Gigabit per second
International System of Units, measurement_unit.measurement_system.weight_units, Kilogram
International System of Units, measurement_unit.measurement_system.energy_units, Kilojoule
International System of Units, measurement_unit.measurement_system.volumetric_flow_rate_units, Cubic metre per second
International System of Units, measurement_unit.measurement_system.length_units, Decimetre
Tonne, measurement_unit.mass_unit.measurement_system, International System of Units
Metre per second squared, measurement_unit.acceleration_unit.measurement_system, International System of Units
Gigabit per second, measurement_unit.unit_of_data_transmission_rate.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.specific_energy_units, Joule per gram
Unit of Radiance, type.type.properties, Radiance in watts per square meter per steradian
Gray per second, measurement_unit.absorbed_dose_rate_unit.measurement_system, International System of Units
Megapascal, measurement_unit.pressure_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.frequency_units, Hertz
Pascal, measurement_unit.pressure_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.radiance_units, Watt per square metre per steradian
International System of Units, measurement_unit.measurement_system.time_units, zeptosecond
International System of Units, measurement_unit.measurement_system.energy_density_units, Joule per cubic metre
Megabit per second, measurement_unit.unit_of_data_transmission_rate.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.magnetic_flux_density_units, Tesla
International System of Units, measurement_unit.measurement_system.length_units, Micrometer
Joule per mole, measurement_unit.molar_energy_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, Kilosecond
International System of Units, measurement_unit.measurement_system.length_units, Hectometre
International System of Units, measurement_unit.measurement_system.pressure_units, Megapascal
International System of Units, measurement_unit.measurement_system.length_units, Millimeter
Henry per metre, measurement_unit.permeability_unit.measurement_system, International System of Units
Gigahertz, measurement_unit.unit_of_frequency.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.magnetic_field_strength_units, Ampere per metre
International System of Units, measurement_unit.measurement_system.data_rate_units, bit per second
Hectometre, measurement_unit.distance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.heat_capacity_units, Joule per kelvin
International System of Units, measurement_unit.measurement_system.angular_acceleration_units, Radian per second squared
Steradian, measurement_unit.solid_angle_unit.measurement_system, International System of Units
Newton, measurement_unit.unit_of_force.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.electric_charge_density_units, Coulomb per cubic metre
Radiance, measurement_unit.dimension.units, Watt per square metre per steradian
Lux, measurement_unit.illuminance_unit.measurement_system, International System of Units
Microsiemens per centimeter, measurement_unit.unit_of_conductivity.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.amount_concentration_units, Micromolar
Radiance in watts per square meter per steradian, type.property.unit, Watt per square metre per steradian
Microgram, measurement_unit.mass_unit.measurement_system, International System of Units
Siemens, measurement_unit.conductance_unit.measurement_system, International System of Units
Square meter, measurement_unit.area_unit.measurement_system, International System of Units
decasecond, measurement_unit.time_unit.measurement_system, International System of Units
Centisecond, measurement_unit.time_unit.measurement_system, International System of Units
Katal per cubic metre, measurement_unit.catalytic_concentration_unit.measurement_system, International System of Units
Kelvin, measurement_unit.temperature_unit.measurement_system, International System of Units
Joule, measurement_unit.energy_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.density_units, Kilogram per cubic metre
Kilogram, measurement_unit.mass_unit.measurement_system, International System of Units
yottasecond, measurement_unit.time_unit.measurement_system, International System of Units
Microsecond, measurement_unit.time_unit.measurement_system, International System of Units
Mole, measurement_unit.substance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.amount_concentration_units, Nanomolar
International System of Units, measurement_unit.measurement_system.inductance_units, Henry
yoctosecond, measurement_unit.time_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.resistivity_units, Ohm meter
Newton metre, measurement_unit.force_moment_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
Microsiemens, measurement_unit.conductance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.length_units, Centimeter
International System of Units, measurement_unit.measurement_system.time_units, Gigasecond
International System of Units, measurement_unit.measurement_system.radioactivity_units, Becquerel
International System of Units, measurement_unit.measurement_system.data_rate_units, Kilobit per second
Lumen, measurement_unit.luminous_flux_unit.measurement_system, International System of Units
Inverse Kelvin, measurement_unit.inverse_temperature_unit.measurement_system, International System of Units
Kilobit per second, measurement_unit.unit_of_data_transmission_rate.measurement_system, International System of Units
Watt per square metre per steradian, measurement_unit.radiance_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.current_units, Ampere
Millisecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.pressure_units, Gigapascal
International System of Units, measurement_unit.measurement_system.frequency_units, Gigahertz
Nanometre, measurement_unit.distance_unit.measurement_system, International System of Units
Hertz, measurement_unit.unit_of_frequency.measurement_system, International System of Units
International System of Units, base.schemastaging.context_name.pronunciation, g.125_p8yyr
International System of Units, measurement_unit.measurement_system.time_units, Microsecond
Ohm meter, measurement_unit.unit_of_resistivity.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.force_units, Newton
Milliliter, measurement_unit.volume_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.luminance_units, Candela per square metre
International System of Units, measurement_unit.measurement_system.electric_field_strength_units, Volt per metre
Floating Point Number, type.type.expected_by, Radiance in watts per square meter per steradian
Decametre, measurement_unit.distance_unit.measurement_system, International System of Units
Joule per gram per kelvin, measurement_unit.specific_heat_capacity_unit.measurement_system, International System of Units
Farad per metre, measurement_unit.permittivity_unit.measurement_system, International System of Units
Candela, measurement_unit.luminous_intensity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.frequency_units, Kilohertz
International System of Units, measurement_unit.measurement_system.acceleration_units, Metre per second squared
Weber, measurement_unit.magnetic_flux_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.energy_units, Joule
Sievert, measurement_unit.dose_equivalence_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.volume_units, Milliliter
International System of Units, measurement_unit.measurement_system.area_units, Square meter
International System of Units, measurement_unit.measurement_system.volume_units, Liter
Ohm centimeter, measurement_unit.unit_of_resistivity.measurement_system, International System of Units
Megasecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, zettasecond
International System of Units, measurement_unit.measurement_system.area_units, Square kilometer
Radiance in watts per square meter per steradian, type.object.permission, m.014_
International System of Units, measurement_unit.measurement_system.viscosity_units, Pascal second
Watt per meter per kelvin, measurement_unit.thermal_conductivity_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.power_units, Kilowatt
Second, measurement_unit.time_unit.measurement_system, International System of Units
Meter, measurement_unit.distance_unit.measurement_system, International System of Units
Becquerel, measurement_unit.radioactivity_unit.measurement_system, International System of Units
Megawatt, measurement_unit.power_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.weight_units, Microgram
International System of Units, measurement_unit.measurement_system.weight_units, Gram
International System of Units, measurement_unit.measurement_system.luminous_intensity_units, Candela
International System of Units, measurement_unit.measurement_system.molar_energy_units, Kilojoule per mole
Nanosecond, measurement_unit.time_unit.measurement_system, International System of Units
exasecond, measurement_unit.time_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.time_units, yoctosecond
Square kilometer, measurement_unit.area_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.capacitance_units, Farad
International System of Units, measurement_unit.measurement_system.length_units, Decametre
Radiance, base.schemastaging.context_name.pronunciation, g.125_qcnsl
International System of Units, measurement_unit.measurement_system.potential_units, Volt
Coulomb, measurement_unit.charge_unit.measurement_system, International System of Units
Volt per metre, measurement_unit.electric_field_strength_unit.measurement_system, International System of Units
International System of Units, user.avh.default_domain.ellerdale_topic.ellerdale_id, 0080-5e5f
Terabit per second, measurement_unit.unit_of_data_transmission_rate.measurement_system, International System of Units
Nanomolar, measurement_unit.amount_concentration_unit.measurement_system, International System of Units
International System of Units, measurement_unit.measurement_system.power_units, Milliwatt
Radiance in watts per square meter per steradian, type.property.unique, true
Volt, measurement_unit.potential_unit.measurement_system, International System of Units

Answer: International System of Units