7. Ferris Company's beginning inventory balance and transactions for January are as follows: Purchases Sales Date Jan. 01 (balance) Units Unit Cost Date Units 8,000 $ 8.00 Jan. 05 4,000 Jan. 10 Jan. 18 6,000 8,000 9.00 Jan. 12 2,000 10.00 Jan. 20 3,000 0 a) Determine the January ending inventory, assuming Ferris employs the FIFO method of inventory costing under a periodic inventory system. $125,000 b) Determine the January ending inventory, assuming Ferris employs the LIFO method of inventory costing under a periodic inventory system. $109,000 c) Determine the January ending inventory, assuming Ferris employs the LIFO method of inventory costing under a perpetual inventory system. $118,000 d) Determine the January cost of goods sold, assuming Ferris employs the average cost method of inventory costing under a periodic inventory system. $81,000