The total cost (in dollars) of manufacturing x auto body frames is C(x) = 90,000 + 400x. (A) Find the average cost per unit if 400 frames are produced. (B) Find the marginal average cost at a production level of 400 units. (C) Use the results from parts (A) and (B) to estimate the average cost per frame if 401 frames are produced. . . . (A) If 400 frames are produced, the average cost is $ per frame. (B) The marginal average cost at a production level of 400 units is $ per frame. (Round to the nearest cent as needed.) (C) Using the results from parts (A) and (B), the estimate of the average cost per frame if 401 frames are produced is $ (Round to the nearest cent as needed.)