Use the following short-run graph concerning a purely competitive firm to answer questions (6) - (8), where q represents the quantity produced by the firm, MC is the marginal cost of the firm, d is the firm's demand curve, ATC is the average total cost of the firm, and AVC is the average variable cost of the firm: [6] At a quantity of 200 , marginal revenue: A. equals $6 B. equals $11 C. equals $2,0 D. cannot be determined since not cnough information is provided. [7] The profit-maximizing quantity for the firm to produce equals: A. 0 B. 200 C. 250 D. 300