Problem 13. Which statement is true of the function 9%) = (a: aha"i, Where a is a constant. (A) 9(33) has no critical points. (B) 9(56) has critical points at x 2 a + 1 and x : 20. (C) 9(33) has critical points at a: = a and a: = 20. (D) x) has a single critical point at m = a. ) 3:) has a single critical point at 3: 2 a 1. ) ) 9( g( g($ has a single critical point at m = a + 1