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Find any critical numbers for f and then use the second derivative test to decide whether the critical number(s) lead to relative maxima or relative minima. If f"(c) =0 or f"(c) does not exist for a critical number c, then the second derivative test gives no information. In this case, use the first derivative test instead. f( x) = 4x - 14x +1 What is/are the critical number(s)? Select the correct choice below and, if necessary, fill in the answer box to complete your choice. O A. The critical number(s) is/are x = (Simplify your answer. Use a comma to separate answers as needed.) O B. There are no critical numbers. Where are the relative extrema? Select the correct choice below and, if necessary, fill in the answer box(es) to complete your choice. O A. There is a relative minimum at x = and a relative maximum at x = (Simplify your answers. Use a comma to separate answers as needed.) O B. There is a relative maximum at x = . There are no relative minima. (Simplify your answer. Use a comma to separate answers as needed.) O C. There is a relative minimum at x = . There are no relative maxima. (Simplify your answer. Use a comma to separate answers as needed.) O D. There are no relative extrema