In a period when costs are declining and inventory quantities are stable, the lowest cost of goods sold would be reported by using the inventory method of

LIFO

Explanation:

To record the lowest cost of goods sold, the ending inventory amount must be high. This would only be high in LIFO whish would not be affected by declining costs.

By using LIFO (Last in First Out) inventory valuation will be based on the value of the earliest goods purchased instead of latest goods purchased as in FIFO (First In First Out)

answer///supply is elastic, and demand is inelastic;