问题
单项选择题
A perfectly competitive firm will continue to increase output so long as which of the following conditions exists（）
A. Marginal revenue is greater than price.
B. Marginal revenue is positive.
C. Market price is greater than marginal cost.
答案
参考答案：C
解析：
A perfectly competitive firm will tend to expand its output so long as the market price is greater than marginal cost since price and marginal revenue are equal. In the short term and long term, profit is maximized when marginal cost and marginal revenue are equal ( i. e. MC = MR).