A perfectly competitive firm maximizes economic profit at the point where a. MR = MC b. slope of MR = slope MC c. slope of TR = slope of TC d. vertical difference between ATC curve and AVC curve is at the greatest e. Marginal Product is at its maximum f. Marginal Cost is at its minimum Group of answer choices only e and f are correct only a, b, and d are correct all answers are correct only a and c are correct only a, c, and d are correct