The Basic Difference Between the Market Supply Curve of an Input

Multiple Choice

The basic difference between the market supply curve of an input and the supply curve of an input to a single perfectly competitive firm is that

A) demand by a single firm can influence the input supply curve, but market demand cannot influence market supply.
B) a single competitive firm always faces a backward-bending input supply curve, whereas the market supply curve infrequently bends backward.
C) the input supply curve for a single firm is perfectly elastic, a condition rarely, if ever, observed in a market supply curve.
D) the input supply curve for a perfectly competitive firm rises more rapidly than the market supply curve.
E) There is no difference; the two supply curves are identical.