The following equations describe the monopolist's demand, marginal revenue, total cost, and the marginal cost: What is the monopolist's profit? Demand: P = 10 - Q Marginal Revenue: MR = 10 - 2Q Total Cost: TC = 6+Q+0.5Q² Marginal Cost: MC = 1+Q a. $10.5 b. $7.5 c. $15 d. $8