If Firms in a Competitive Industry Are Earning Positive Economic

If firms in a competitive industry are earning positive economic profits,in the long run we expect

A) the demand curve for the product will shift to the left,so that the price of the product will fall.
B) the supply curve for the product will shift to the right as new firms enter the industry,causing industry output to increase and price to fall.
C) there would be no change in the industry as long as P = MC for the individual firms.
D) the individual firms will lower their price to discourage new firms from entering the industry.
E) the government would intervene and force the firms to lower prices.