The Major Difference Between Monopolistic Competition and Monopoly Is

The major difference between monopolistic competition and monopoly is

A) monopoly is a price setter and a firm in monopolistic competition is a price taker.
B) only a monopoly can earn an economic profit in the long run.
C) only a firm in monopolistic competition can earn an economic profit in the short run.
D) how the quantity of output is determined.
E) only firms in monopolistic competition are protected by barriers to entry.