Let g(x) be the inverse of an invertible function f(x) which is differentiable for all real x, then g"(f(x)) equals
(A) \(- \frac{f"(x)}{(f'(x))^3}\)
(B) \(\frac{f'(x)f"(x)- (f'(x))^3}{f'(x)}\)
(C) \(\frac{f'(x)f"(x)- (f'(x))^2}{(f'(x))^2}\)
(D) none of these