Which Is Not True of a Perfectly Competitive Market

Which is not true of a perfectly competitive market?

A) The typical industry demand curve is downward sloping.
B) There is no incentive to innovate since economic profit is zero in the long-run.
C) If the long-run average total cost curve is horizontal in the relevant range of production, perfectly competitive firms can be various sizes in long-run equilibrium.
D) At long-run equilibrium, economic profit is less than accounting profit.