7. If f is a differentiable function and f(0) = -1 and f(4) = 3, then which of the following must be true? I. There exists a c in (0,4] where f(c) = 0.
II. There exists a c in (0,4] where f'(c) = 0.
III. There exists a c in (0,4] where f'(c) = 1.
(A) I only
(B) II only
(C) I and II only
(D) I and III only
(E) I, II, and III