An assumption about cost flow is necessary:
a. because it is required by the income tax regulation
b. even when there is no change in the purchase price on inventory
c. only when the flow of goods cannot be determined
d. because prices usually change, and tracking which units have been sold is difficult

The correct answer is letter "D": because prices usually change, and tracking which units have been sold is difficult.

Explanation:

Costs flow assumptions are the result of many factors. Inflation, changes in costs as a result of changing prices, and inventory sales tracking per unit are the most important. Cost flow assumptions analyze how costs are removed from a firm's inventory and reported in the account of Cost of Goods Sold using costing methods such as the FIFO (First-in, First-out), LIFO (Last-in, First-Out), and the Weighted Average.

answer; i believe the correct answer is energy star;

answer; (a) searching for information can be done quickly;