-The Figure Above Shows a Firm in Monopolistic Competition

-The figure above shows a firm in monopolistic competition. If all firms in the industry have the demand and cost curves illustrated in the figure, then in the long run

A) some firms will have exited the industry.
B) some firms will have entered the industry.
C) firms will have neither entered nor exited the industry.
D) we cannot tell if firms will either have entered or exited the industry.