The demand curve for the product of a monopoly seller is reliably estimated as: Q d = 300 - 15 P (P is measured in $). If the Marginal Cost for the monopolist is constant at $5 per unit of output, the monopolist would maximize revenue by setting a price (to the nearest 10 c) of:
A. $15.00
B. $10.00
C. $7.50
D. $4.50
Explain your answer.