Setting aside the argument proposed in the Schumpeterian hypotheses, maximum efficiency is assured in

a. monopoly because monopolists have the ability to choose where to produce and will obviously produce where costs are minimized.

b. monopolistic competition because firms produce differentiated products so that they can pick any price, but they still have to compete, which drives costs to a minimum.

c. perfect competition, but only in the long run.

d. perfect competition, but only in the short run.

e. all market structures, but only in the long run because they all try to maximize profit and that drives all to maximum efficiency.