Find the critical points, domain endpoints, and local extreme values for the function. y=6x16-x2 ***** What is/are the critical point(s) or domain endpoint(s) where f' is undefined? Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. The critical point(s) or domain endpoint(s) where f' is undefined is/are at x= 4, -4. (Simplify your answer, including any radicals. Use integers or fractions for any numbers in the expression. Use a comma to separate answers as needed.) B. There are no critical points or domain endpoints where f' is undefined. What is/are the critical point(s) where f' is 0? Select the correct choice below and, if necessary, fill in the answer box to complete your choice. OA. The critical point(s) where f' is 0 is/are at x= (Type an exact answer, using radicals as needed. Use a comma to separate answers as needed.) OB. There are no critical points where f' is 0.