Comparing the Short-Run and Long-Run Profit-Maximizing Positions of a Perfectly

Comparing the short-run and long-run profit-maximizing positions of a perfectly competitive firm,which statement is true?

A) Price will equal marginal cost in the short run,but not necessarily in the long run.
B) Economic profit may exist in the short run and in the long run.
C) The firm will produce at minimum average cost in both the short and long run.
D) Price should equal average cost in the long run,but not necessarily in the short run.
E) The firm may have unexploited economies of scale in both the short run and the long run.