Which of the Following Is False of Perfectly Competitive Firms

Which of the following is false of perfectly competitive firms?

A) Because the short run is too brief for new firms to enter the market, the market supply curve is the horizontal summation of the supply curves of existing firms.
B) As new firms enter an industry where sellers are earning economic profits, the result will include a reduction in the equilibrium price.
C) In a constant-cost industry, the industry does not use inputs in sufficient quantities to affect input prices.
D) In a constant-cost competitive industry, the long-run effect of an increase in demand is an increase in industry output but no change in the industry price.
E) None of the above are false; all are true.