Find all critical numbers for the following function. Then use the second-derivative test on each critical number to determine whether it leads to a local maximum or minimum. f(x) = -2x-3x+36x+6 What is the second derivative of f(x)? f'(x)= Find all critical numbers and determine whether they lead to a local maximum or minimum. Select the correct choice below and, if necessary, fill in the answer box(es) to complete your choice. OA. The critical number(s) is/are x= There is no local maximum and no local minimum. (Use a comma to separate answers as needed.) OB. There are no critical numbers. OC. The critical number(s) is/are x= There is a local maximum at x= There is a local minimum at x= (Use a comma to separate answers as needed.) OD. The critical number(s) is/are x = There is no local maximum. There is a local minimum at x= (Use a comma to separate answers as needed.) OE. The critical number(s) is/are x= There is a local maximum at x= There is no local minimum. (Use a comma to separate answers as needed.)