Periodic inventory by three methods The units of an item available for sale during the year were as follows: Jan. 1 Inventory 2,900 units at $6 Feb. 17 Purchase 2,900 units at $7 Jul. 21 Purchase 2,900 units at $8 Nov. 23 Purchase 1,300 units at $9 There are 1,600 units of the item in the physical inventory at December 31. The periodic inventory system is used. This information has been collected in the Microsoft Excel Online file. Open the spreadsheet, perform the required analysis, and input your answers in the questions below. Open spreadsheet a. Determine the inventory cost by the first-in, first-out method. b. Determine the inventory cost by the last-in, first-out method. c. Determine the inventory cost by the weighted average cost method. Round your answer to the nearest dollar.