The fact that money "enables people to transfer purchasing power from the present to the future re money.
A)
unit of value
store of value
C)
unit of account
Eliminate
D)
medium of exchange

store of value

Explanation:

Store of value is the ability of money to be saved for future use without deteriorating in value.  Money is known to retain its value for long periods. This feature allows trade to be conducted on credit as business people are assured of getting a fair value of their commodities in the future.

Store of value means that money retains its worth for a considerable length of time.  

the answer is account d

answer; sales of books;