4. What is the main difference between a competitive firm and a monopoly firm? a. The number of customers served by the firm. b. Monopoly firms are more efficient and therefore have lower costs. c. Monopoly firms can generally carn positive profits over a longer period of time. d. Monopoly firms enjoy government protection from competition. 7 A competitive firm's profit maximizing prices $15. Ar MC MR, the output 100 units, Arthuis loud of producten age total costs are S. The firm's poligare 50 in the short run and long run So in the short and zero in the long run $500 in the short and long run So in the short run and in the Hatarun Accessibility investigate o