A monopolist with a straight-line demand curve finds that it can sell two units at $12 each or 12 units at $2 each.  Its fixed cost is $20 and its marginal cost is constant at $3 per unit.
a) Draw the MC, ATC, MR, and demand curves for this monopolist.
b) Illustrate at what output level would the monopolist produce?
c) Illustrate at what output level would a perfectly competitive firm produce?