A firm is observed making monopoly profits. Using dynamic analysis of monopoly, one would argue that

a.the firm is inefficient and should be dealt with by antitrust or regulatory authorities.

b.the firm's profits should be taxed away.

c.the monopoly profits are not a concern as long as the firm is producing where P =MC.

d.the profits are a reward for successfully developing a new product and the firm should not be dealt with by antitrust or regulatory authorities.