Strait Co. manufactures office furniture. During the most productive month of the year, 3,000 desks were manufactured at a total cost of $84,200. In the month of lowest production, the company made 1,100 desks at a cost of $61,100. Using the high-low method of cost estimation, total fixed costs are Oa. $61,100 Ob. $84,200 Oc. $23,100 Od. $47.720