Answer:
B
Explanation:
Money has several functions, one of its principal function is using it as unit of account. By comparing the amount in dollars spent on running a car yearly to annual earnings instead of keeping track in terms of gasoline cost and quarts of oil shows that money has been used as a unit of account.
This means that the amount of gasoline gallons bought and quarts of oil has been essentially replaced by the cost of these purchases and hence avail is the power to use money as a unit of account