If f(x) = e^x, which of the following is equal to f'(e)? a. lim h->0 e^x + h/h b. lim h->0 e^x + h - 1/h c. lim h->0 e^x + h - e^e/h d. lim x->e e^x _ e^e/x - e e. lim x->0 e^e - e/x