Given the graph of y = f(x) below, at which of the marked I-values can the following statements be true? x1 x2 x5 (For each question, enter your answer as a comma-separated list, eg, x1,x3,x5. Enter none if no points satisfy the given condition) A. f(x) > 0 at z = B. f'(z) > 0 at 1 = C. f(z) is increasing at a = D. f'(x) is increasing at = = E. The slope of f(x) is negative at a =