Task: Class Definition Understanding (ontology: Earth_Environment/OBOE)

Which of the following definitions best describes 'Millibar'?

A. A the concept is a unit pressure commonly used in oceanography because it's value is generally equivalent to depth in meters. 1 dbar = 0.1 bar = 10 kPa
B. The the concept is a unit of length equal to 0.1 nanometre.
C. A the concept is a unit pressure commonly used in meterology. 1 mbar = 0.001 bar = 0.1 kPa = 1 hPa (hectopascal)
D. The the concept (symbol: the concept) is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. 

It is not an SI or cgs units, but accepted for use with the SI. The the concept is widely used in descriptions of pressure because it is only about 1% smaller than "standard" atmospheric pressure, and is legally recognized in countries of the European Union.

Common derivatives are millibar (meteorology) and decibar (oceanography)

Answer: A the concept is a unit pressure commonly used in meterology. 1 mbar = 0.001 bar = 0.1 kPa = 1 hPa (hectopascal)