The Reason a Profit-Maximizing Natural Monopolist Cannot Set Price Equal

The reason a profit-maximizing natural monopolist cannot set price equal to marginal cost is that it would:

A) then be forced to produce more than it could sell.
B) then be forced to produce more than the socially optimal level of output.
C) earn excessive profits, which would attract new firms into the market.
D) suffer losses since price would be less than average cost.