4. Is monopolistic competition efficient? Suppose that a firm produces baseball bats in a monopolistically competitive market. The following graph shows its demand curve, marginal revenue (MR) curve, marginal cost (MC) curve, and average total cost (ATC) curve. Place a black point (plus symbol) on the graph to indicate the long-run monopolistically competitive equilibrium price and quantity for this firm. Next, place a grey point (star symbol) to indicate the minimum average total cost the firm faces and the quantity associated with...