A manufacturer incurs the following costs in producing x water ski vests in one day, for 0

A manufacturer incurs the following costs in producing x water ski vests in one day, for O < x < 150: fixed costs, $500; unit production cost, $20 per vest; equipment maintenance and repairs, 0.05x dollars. So, the cost of manufacturing x vests in one given day is given by where (A) What is the average cost C(x) per vest if x vests are produced in one day? (B) Find the critical numbers of C(x), the intervals on which the average cost per vest is decreasing, the intervals on which the average cost per vest is increasing, and the local extrema. Do not graph. (B) Find the critical numbers of C(x). Select the correct choice below and, if necessary, fill in the answer box to complete your choice. The critical number(s) is/are x = . (Use a comma to separate answers as needed.) @ B. There are no critical numbers of C(x). The average cost per vest is decreasing on the interval(s) 0. (Type your answer in interval notation. Use a comma to separate answers as needed.) The average cost per vest is increasing on the interval(s) D. (Type your answer in interval notation. Use a comma to separate answers as needed.) Find the local extrema. Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice. (Simplify your answer.) O D. is a local minimum. There is no local maximum. is a local maximum. There is no local minimum. is a local minimum and = is a local maximum. There are no local extrema.