. Choose the correct answer below. A. It is false that the function is not differentiable at x because its derivative is undefined at x. B. It is false that the function is not differentiable at x because its derivative is continuous at x. C. It is true that the function is not differentiable at x because its derivative is undefined at x. D. It is true that the function is not differentiable at x because its derivative is continuous at x.