The Difference Between a Monopolist and a Monopolistic Competitor Is

The difference between a monopolist and a monopolistic competitor is that:

A) a monopolist equates marginal revenue and marginal cost whereas a monopolistic competitor equates price and marginal cost.
B) the average total cost curve of a monopolistic competitor is tangent to the demand curve in long-run equilibrium, but the average total cost curve of a monopolist can be in a position below the price in long-run equilibrium.
C) the average total cost curve of a monopolist is tangent to the demand curve in long-run equilibrium, but the average total cost curve of a monopolistic competitor can be in a position below the price in long-run equilibrium.
D) the average total cost curve of a monopolist is tangent to the demand curve in long-run equilibrium, but the average total cost curve of a monopolistic competitor can be in a position above the price in long-run equilibrium.