A company purchased 500 units for $30 each on January 31. It purchased 600 units for $36 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 firstin, firstout (FIFO) inventory costing method? (Assume that the company uses a perpetual inventory system.)

A. $560

B. $16560

C. $13800

D. $13240