Which of the Following Is True

Which of the following is true?

A) Monopolistic competitive firms do not experience the law of diminishing marginal returns when they produce output.
B) Monopolistic competitive firms face a downward-sloping demand curve and a horizontal marginal cost curve.
C) There are many buyers and few sellers in the theory of monopolistic competition.
D) Monopolistic competitors are said to underutilize their present plant size.
E) none of the above