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

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

A. A mass unit which is equal to one thousandth of one millionth of a gram or 10^[-9] g.
B. A mass unit which is equal to one thousandth of a kilogram or 10^[-3] kg.
C. A mass unit which is equal to one millionth of a gram or 10^[-6] g.
D. A mass unit which is equal to one thousandth of a gram or 10^[-3] g.

Answer: A mass unit which is equal to one thousandth of one millionth of a gram or 10^[-9] g.