4 The function f (9:) = 5:1:E is not differentiable at x = 0. Why? 0 A. At x = 0, the graph has a corner. 0 B. At x = 0, the graph is discontinuous. O C. At x = 0, the graph has a cusp. O D. At x = 0, the graph has a vertical tangent line. 0 E. At x = O, nDeriv is large