How do you find the derivative of the product of two functions that are differentiable at a point? Select the correct answer below. O A. d f(x) dx g(x) =f (xx)g(x) +f(x)g'(x) O B. d f(x) g(x)f'(x) -f(x)g'(x) dx g(x) [g(x)]2 O C. g(x)f' (x) -f(x)g'(x) dx [f(x) . g(x)] = [g(x)] OD. d dx [f(x) . g(x)] =f'(x)g(x) + f(x)g'(x)