Detailed Answer
Answer (B) is correct.
In a period of falling costs, FIFO results in higher cost of goods sold than
the weighted-average method. FIFO includes the higher, earlier costs in
cost of goods sold, and the weighted-average method averages the later,
lower costs with the higher, earlier costs. Thus, a change from FIFO to
weighted-average costing reduces cost of goods sold and increases
reported profit.