Complete parts a through c for the given function. f(x)=-4x²+3x+1; [-3,3] a. Locate the critical point(s) of f. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. OA. The critical point(s) is (are) at x = ☐. (Simplify your answer. Use a comma to separate answers as needed.) B. The function does not have a critical point.