Suppose f (:) = 2 - 1 for x x 1 and f (x) = a cos be for > > 1. What values of a and b will ensure that f (x) is differentiable for all values of x? O A. a = - 4, b= * O B. Q = - b = O C. a = - b = O D. a = - b = O E. a = , b =