Which of the Following Statements Is Correct

Which of the following statements is correct?

A) If the monopolist's marginal revenue is greater than its marginal cost, the monopolist can increase profit by selling more units at a lower price per unit.
B) If the monopolist's marginal revenue is greater than its marginal cost, the monopolist can increase profit by selling fewer units at a higher price per unit.
C) When a monopolist produces where price equals the minimum of average total cost, it earns a positive economic profit.
D) If the monopolist is earning a positive economic profit, it must be producing where MR = MC.