In Which of the Following Situations Does Money Serve as a Unit

In which of the following situations does money serve as a unit of account?

A) Goods have a value expressed in the same currency, thus allowing comparisons.
B) Goods have a value expressed in both a fiat money and commodity money.
C) Goods have a value expressed in terms of both a commodity money and commodity-backed money.
D) Goods cannot be assigned a value.
E) Goods have a value that changes over time.