If a firm is operating in a monopolistically competitive market, then in the long run: A. the firm will maximize its profit by producing the output level at which the marginal revenue is minimized. B....

A. the firm will maximize its profit by producing the output level at which the marginal revenue is minimized.

B. the firm will earn zero economic profit.

C. the firm will maximize its profit by producing the output level at which the average cost is minimized.

D. all of the above