The Existence of Imperfectly Competitive Firms Implies a Market Failure

The existence of imperfectly competitive firms implies a market failure because

A) their market power allows them to deceive consumers.
B) those firms will maximize profits by setting price above marginal cost.
C) they do not produce a productively efficient level of output.
D) they lead to a socially undesirable distribution of income.
E) there is no way to prevent these firms from abusing their market power.