Which one of the following statements is TRUE for BOTH perfect competition and monopolistic competition?

Question

Quizplus · Accepted Answer

Both perfect competition and monopolistic competition result in zero economic profit in the long run. In perfect competition, firms are unable to earn economic profit due to the existence of many firms producing homogeneous products. In monopolistic competition, firms are able to earn positive economic profit in the short run due to product differentiation, but competition from other firms entering the market drives down prices and eliminates economic profit over time. 
A) This statement is only true for monopolistic competition, as firms in perfect competition do not face a downward sloping demand curve. 
B) This statement is only true for perfect competition, as firms in monopolistic competition produce differentiated products. 
D) This statement is true for monopolistic competition, but not for perfect competition, as firms in perfect competition only compete on price.

Which One of the Following Statements Is TRUE for BOTH