Why, if competitive firms are earning economic profits in the short run, are they unable to earn them in the long run?
a)If firms are making short-run profits, consumers will no longer be willing to buy the good and enrich the firm's owners.
b)firms will enter the industry with better technology and generate more profits in the long run.
c)firms will exit the industry and the loss of competition will drive profits to zero in the long run.
d)firms will enter the industry and greater competition will drive profits to zero in the long run.