Task: Instance Description Understanding (ontology: Sciences/Computer_Science)

Which of the following definitions best describes the instance 'micromolar'?

A. A dimensionless concentration unit which denotes the volume of the solute in mL per 100 mL of the resulting solution.
B. A volume per unit volume unit which is equal to one millionth of a liter of solute in one liter of solution.
C. A unit of molarity which is equal to one millionth of a molar or 10^[-6] M.
D. A mass density unit which is equal to mass of an object in grams divided by the volume in deciliters.

Answer: A unit of molarity which is equal to one millionth of a molar or 10^[-6] M.