Answer:
Option (B) is correct.
Step-by-step explanation:
Unit of account:
There are some functions of money or we can say that characterstics of money:
(a) Medium of exchange
(b) Store of value
(c) Unit of account
(d) Standard of deferred payments
Sea shells are precious items but one cannot properly split divide those sea shells into small denominations like money does. Money is easily storable, people use as a medium of exchange and unit of account.
By unit of account we mean that we can easily measure the value of goods and service and many things in monetary terms but we cannot measure in terms of sea shells.
That's why sea shells unfit to act as money today.