The following information is available for a company's cost of sales over the last five months. Month January February March April Units sold 330 730 1,250 2,050 Cost o sales $28,200 $33,500 $45,500 $57,500 Using the high-low method, the estimated variable cost of sales per unit sold is: O $36.01 O $85.45 O $28.05 $36.40 O $17.03