The following inventory details of ABC company Date Cost Description Units 5 $10 1/1/2020 Opening inventory 8 Purchases 5/1/2020 $15 10/1/2020 Sales 7 10 $20 15/1/2020 Purchases 8 20/1/2020 Sales By using Period Inventory System, calculate: Cost of Goods Sold and Cost of Ending Inventory under a) FIFO b) LIFO c) AC