Which statement is true?
(A)If f(x) is continuous at x = c, then f′(c) exists. (B)If f′(c) = 0, then f has a local maximum or minimum at (c, f (c)). (C)If f′′(c) = 0, then the graph of f has an inflection point at (c, f (c)). (D)If f is differentiable at x = c, then f is continuous at x = c.
D