A company purchased 400 units for $30 each on January 31. It purchased 480 units for $36 each on February 28. It sold a total of 540 units for $40 each from March 1 through December 31 What is the cost of ending inventory on December 31 if the company uses the first-in, first-out (FIFO) inventory costing method? (Assume that the company uses a perpetual inventory system.) OA. $9,640 OB. $10,200 OC. $12,240 D. $560