12. If f(x) = (1 - 5x2)2 then f"(0) is equal to A. 1 B. 20 C. -20 D. None of the above 13. If f (x) = >" , then f'(x) equals A. B. ( * * - 1 ) C. 0 D. None of these 14. A critical number occurs at A f(c) = 0 B. f(c) = 0 C. F(x) =0 D. all of the above