Classification of cost is useful .a.to identify costs.b.to find gross profit.c.to identify efficiency.d.to find net profit.

The classification of costs is indeed useful for several reasons:

a. To identify costs: Classifying costs helps in understanding where the company's money is going. It helps in tracking and managing the costs effectively.

b. To find gross profit: Gross profit is calculated by subtracting the cost of goods sold (COGS) from the total revenue. COGS includes direct costs related to the production of goods sold by a company. Therefore, classifying costs helps in calculating gross profit.

c. To identify efficiency: By classifying costs, a company can identify areas where it is spending more and can work on strategies to reduce those costs, thereby increasing efficiency.

d. To find net profit: Net profit is calculated by subtracting all the expenses (including operational, interest, taxes, etc.) from the gross profit. Therefore, classifying costs helps in calculating net profit.