The Deering Manufacturing Company's short-run average cost function in 2012 was AC = 3 + 4Q where AC is the firm's average cost (in dollars per pound of the product), and Q is its output rate. a. Obtain an equation for the firm's short-run total cost function. b. Does the firm have any fixed costs? Explain. c. If the price of the Deering Manufacturing Company's product (per pound) is $3, is the firm making profit or loss? Explain. d. Derive an equation for the firm's marginal cost function.