5. Let f be a continuous and differentiable function for all real numbers. The only critical points for f are located
at x = -3 and x = 5. If F"(x) = 2x - 2, which of the following must be true?
I. f has a relative maximum at x = -3.
II. f has a relative maximum at x = 5.
III. f has a point of inflection at x = 1.
(A) I only
(B) II only
(C) III only
(D) I and III only
(E) II and III only