A company purchased 300 units for $30 each on January 31. It purchased 400 units for $40 each on February 28, It sold a total of 450 units for $90 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. $250 OB. $15,000 OC. $7,500 OD. $10,000