One Difference Between Monopoly and Monopolistic Competition Is That

One difference between monopoly and monopolistic competition is that

A) the monopolist can earn positive economic profits in the long run, whereas the monopolistic competitor will earn zero economic profit in the long run.
B) the monopolist seeks to maximize profit, whereas the monopolistic competitor does not.
C) the monopolist produces the quantity at which marginal revenue equals marginal cost, whereas the monopolistic competitor does not.
D) the monopolist faces a downward-sloping demand curve, whereas the monopolistic competitor does not.