The Demand Curve Facing a Monopolist Is D(p) =

The demand curve facing a monopolist is D(p) = if p is 20 or smaller and D(p) = 0 if p > 20. The monopolist has a constant marginal cost of $1 per unit produced. What is the profit-maximizing quantity of output for this monopolist?

A) 4
B) 3
C) 2
D) 5
E) It cannot be determined from the information given.