Can you please help me to do question no. C with proper explanation?

MPREHENSIVE PROBLEM The Montclair Corporation had the following inventory transactions for its only product during 2018 2,000 units @ $27.00 each 3,000 units @ $28.40 each 1,200 units @ $31.25 each ( Purchases February 15. April 20 October 25 Sales March 1. June 12 August 10 December 14 1.200 units @ $50.00 each 2,000 units @ $52.00 each 1,000 units @ $53.00 each 1,600 units @ $55.00 each The Montclair Corporation had 1,000 units in its January 1, 2018, beginning inventory with a unit on of $24 each. Montclair uses the periodic inventory system. Required a. Determine the cost assigned to Montclair's December 31, 2018, ending inventory and Montclair's cost of goods sold for 2018 under each of the following inventory costing methods: 1. Weighted-average cost 2. FIFO 3. LIFO b. Determine Montclair's gross profit for 2018 under each of the following inventory costing methods: 1. Weighted average cost 2. FIFO 3. LIFO c. Determine Montclair's inventory turnover and days' sales in inventory for 2018 under each of the following inventory costing methods: 1. Weighted average cost 2. FIFO 3. LIFO