A hotdog vendor must pay a monthly fee to operate a food cart in the city park. The cost in dollars of selling x hundred hotdogs in a month can be approximated by C(x)=170+75x. Complete parts (a) through (d) below. (a) Find the average-cost function. The average-cost function is C(x)- (b) Find and interpret the average cost at sales levels of 1500 hotdogs and 4000 hotdogs. The average cost at sales levels of 1500 hotdogs is $100 hotdogs (Round to the nearest cent as needed.) Interpret these results, choose the correct answer below. Take the sales level of 1500 hotdogs as an example. Select the correct choice below and fill in the answer box to complete your choice. OA. At a sales level of 1500 hotdogs, the average cost is $ per 100 hotdogs OB. At a sales level of 1500 hotdogs, if an additional 100 hotdogs are sold, the average cost increases by approximately $ per 100 hotdogs. (c) Find the marginal average-cost function The marginal average-cost function is C'(x)- (d) Find and interpret the marginal average cost at sales levels of 1500 hotdogs and 4000 hotdogs. The marginal average cost at sales levels of 1500 hotdogs is $100 hotdogs) (Round to the nearest cent as needed.) Interpret these results, choose the correct answer below. Take the sales level of 1500 hotdogs as an example. Select the correct choice below and fit in the answer box to complete your choice. OA. At a sales level of 1500 hotdogs, the average cost is $ per 100 hotdogs.