Select the true statements regarding a graph of f and its derivatives. ( If f' > 0 and f" 0, then f is increasing at an increasing rate, or f is decreasing at a decreasing rate. If s' (c) . S" (c) = 0, then (c, f (c)) is a local extreme value. If f" (c) = 0, then (c, f (c)) is a point of inflection. If f' and f" have signs that change from +- to -- at x = c, then f has a local maximum at c