Harris Bearing Company uses the periodic inventory system to account for its inventory. The following information was available from the company's inventory records for October: Purchases 10/1 (balance)2,400 units @$10 10/123,000 units @$5 10/251,500 units @$9 Sales 10/143,800 unites @$16 10/301,700 units @21 Requirements: 1. Calculate cost of goods sold and gross profit to be reported on Harris's Income Statement of October by using a. average cost method. b. FIFO costing method. c. LIFO costing method.