单选题 If a monopolistically competitive industry becomes perfectly competitive, each firm's long-run average total cost per unit sold will most likely:
A. decrease.
B. remain the same.
C. increase.

【正确答案】 A
【答案解析】[解析] 当垄断竞争变为完全竞争后，由于产品没有差异化，竞争会加剧，导致产品价格下降，产量上升，长期的平均总成本下降。