If f is differentiable at a, must f be continuous at a? Question content area bottom Part 1 Choose the correct answer below. A. No, if f is differentiable at a and does not have a vertical tangent at a, then f is continuous at a. B. No, if f is differentiable at a and positive at a, then f is continuous at a. C. Yes, if f is differentiable at a, then f is continuous at a. D. No, if f is differentiable at a and does not have a corner at a, then f is continuous at a