On January 1, 2022, DEF Corporation purchased 1,000 units of inventory at a cost of $10 per unit. On January 31, 2022, the company purchased an additional 2,000 units of inventory at a cost of $12 per unit. During the month of February, DEF sold 2,500 units of inventory.

a) Calculate the company's cost of goods sold for the month of February using the FIFO inventory costing method.

b) Calculate the company's ending inventory balance as of February 28, 2022, using the LIFO inventory costing method.