Q20 please answer all the questions

Consider the following cost function. a. Find the average cost and marginal cost functions. b. Determine the average and marginal cost when x = a. c. Interpret the values obtained in part (b). C(x) = 0.02x3 +0.7x2 + 60x+ 120, Oxs 1500, a = 1000 a. The average cost function is C(x) = The marginal cost is function is C'(x) = b. The average cost when x = a is $ . (Round to two decimal places as needed.) The marginal cost when x = a is $ . (Round to two decimal places as needed.) c. Choose the correct interpretation of the average cost when x = a. O A. The average cost per item is about $20,760.12 when 1000 items are produced. O B. The cost of producing the 1001st item is about $61,460.00. O C. The cost of producing the 1001st item is about $2,375.36. O D. The cost of producing 1000 items is about $19,460.12. Choose the correct interpretation of the marginal cost when x = a. O A. The cost of producing 1000 items is about $19,460. 12. B. The cost of producing the 1001st item is about $61,460.00. O C. The cost of producing 1001 items is about $975.36. O D. The average cost per item is about $20,760.12 when 1000 items are produced