A company purchased 500 units for $30 each on January 31. It purchased 650 units for $39 each on February 28. It sold a total of 640 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.) ... A. $140 B. $19,890 C. $15,160 D. $15,300