plz answer thsi question quick (will like it up c:)

Strait Co. manufactures office furniture. During the most productive month of the year, 3,500 desks were manufactured at a total cost of $84,400. In the month of lowest production, the company made 1,110 desks at a cost of $56,200. Using the high-low method of cost estimation, total fixed costs are Oa. $28,200 Ob. $43.100 Oc. $56,200 Od. $84,400