Strait Co. manufactures office furniture. During the most productive month of the year, 3,800 desks were manufactured at a total cost of $84,600. In the month of lowest production, the company made 1,250 desks at a cost of $56,200. Using the high-low method of cost estimation, total fixed costs are Oa. $84,600 Ob. $28,400 Oc. $42,268 Od. $56,200