How Do Competitive Firms and Monopolists Differ

Multiple Choice

How do competitive firms and monopolists differ

A) A competitive firm cannot choose its level of output; a monopolist chooses its level of output.
B) A competitive firm's short-run profit is always zero; a monopolist can have a positive short-run profit.
C) A competitive firm's marginal-revenue curve is horizontal; a monopolist's marginal-revenue curve is downward sloping.
D) A competitive firm sets price equal to marginal cost; a monopolist sets price equal to marginal revenue.