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

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

A. A dimensionless concentration unit which denotes the volume of the solute in mL per 100 mL of the resulting solution.
B. A unit of molarity which is equal to one millionth of a molar or 10^[-6] M.
C. A unit of molarity which is equal to 10^[-12] M.
D. A unit of concentration which expresses a concentration of 1 mole of solute per liter of solution (mol/L).

Answer: A unit of molarity which is equal to 10^[-12] M.