Which of the Following Is True of a Profit-Maximizing Competitive

Which of the following is true of a profit-maximizing competitive firm in the long run?

A) The firm produces at the point where price is equal to marginal cost.
B) The firm produces at the point where average cost equals marginal cost when average cost is at its minimum point.
C) The demand curve faced by all firms in the industry is downward sloping.
D) The firm makes positive economic profit in the long run.
E) In the long run,there is a deadweight loss in a competitive market.