A company purchased 100 units for $30 each on January 31. It purchased 400 units for $20 each on February 28. It sold a total of 470 units for $110 each from March 1 through December 31. If the company uses the last-in, first-out inventory costing method, calculate the amount of ending inventory on December 31. (Assume that the company uses a perpetual inventory system.) A) $600 B) $2.400 (1) C) $30 D) $900