Which ONE of the Following Applies to a Profit- Maximising

Which ONE of the following applies to a profit- maximising monopoly but not to a profit- maximising perfectly competitive firm?

A) Average revenue equals price.
B) The most profitable output is where marginal cost equals marginal revenue.
C) Marginal cost equals average cost at the output where the latter is at the minimum.
D) Marginal revenue is not equal to average revenue.