Which Statement Is TRUE of Firms in Both Perfect Competition

Multiple Choice

Which statement is TRUE of firms in both perfect competition and monopolistic competition?

A) The long-run price is equal to marginal revenue,marginal cost,and average total cost.
B) Long-run economic profits are equal to zero.
C) The long-run level of output is at the point where average total cost is minimized.
D) Price is equal to marginal cost,ensuring that the efficient level of output is produced.