Answer:
B. LIFO.
Step-by-step explanation:
As the costs are declining the company should LIFO inventory method that would maximize the gross profit. When prices are increasing FIFO is usd to maximize the gross profit. But as they are decreasing the reverse would give the desired values.
In case the prices are increasing
FIFO assigns the lowest amount to cost of goods sold yielding the highest gross profit
LIFO assigns the highest amount cost of goods sold yielding the lowest gross profit and net income, which also yields a temporary tax advantage by postponing payment of some income tax
So we use LIFO to maximize the profit in case of decreasing costs.