The total cost (in dollars) of manufacturing x auto body frames is C(x) = 70,000+400x. (A) Find the average cost per unit if 500 frames are produced. (B) Find the marginal average cost at a production level of 500 units. (C) Use the results from parts (A) and (B) to estimate the average cost per frame if 501 frames are produced. (A) If 500 frames are produced, the average cost is $ 540 per frame. (B) The marginal average cost at a production level of 500 units is $ 0.8 per frame. (Round to the nearest cent as needed.)