单选题 Which of the following is least accurate regarding the relationship between price (P) , marginal revenue (MR) , average total cost (ATC), and marginal cost (MC) at the profit maximizing output under monopoly?

A. P=MR
B. MR=MC.
C. P＞MＣ.

【正确答案】 A

【答案解析】To maximize profit, all firms expand output until marginal revenue equals marginal cost. Price is determined from the demand curve, which is above the marginal revenue curve since a monopoly faces a downward sloping demand curve.