A company purchased 300 units for $20 each on January 31. It purchased 100 units for $40 each on February 28. It sold a total of 160 units for $100 each from March 1 through December 31. If the company uses the last - in, first-out inventory costing method, calculate the cost of ending inventory on December 31. (Assume that the company uses a perpetual inventory system.) OA. $19,200 OB. $240 OC. $4,800 OD. $9,600