Refer to the Accompanying Graph

Refer to the accompanying graph.If all firms in the industry are the same as the monopolistically competitive firm shown,the long run will reflect:

A) firms leaving the industry.
B) all firms earning positive economic profits.
C) some firms earning positive economic profit and others experiencing economic loss.
D) competition from new firms that enter the industry.
E) all firms earning economic profit of exactly $300 per day.