E6-15 Inventory by three methods; cost of merchandise sold The units of an item available for sale during the year were as follows: Jan. 1 Apr. 10 Sept. 30 Dec. 12 Inventory Purchase Purchase Purchase 42 units at $180 58 units at $195 20 units at $204 30units at $210 There are 37 units of the item in the physical inventory at December 31. The periodic inventory system is used. Determine the inventory cost and the cost of merchandise sold by three methods, presenting your answers in the following form Cost Inventory Sold Inventory Method a. First-in, first-out .b. Last-in, first-out C. Average cost ?AI/O ock