Suppose a perfectly competitive firm faces the following situation: P = $9, output = 4,000, ATC = $8, AVC = $6, and MC = $9. How can someone determine whether this firm's market is productively efficient?a. It is not in equilibrium because MC = AVC = P = ATC at long-run equilibrium. b. It is in equilibrium because MC = P = AVC = ATC at long-run equilibrium. c. It is in equilibrium because MC = P = MR = SRATC at long-run equilibrium. d. It is not in equilibrium because MC = ATC = MR = P at long-run equilibrium