Periodic Inventory by Three Methods The units of an item available for sale during the year were as follows: There are 4 units of the item in the physical inventory at December 31. The periodic inventory system is used. a. Determine the inventory cost by the first-in, first-out method. 4 b. Determine the inventory cost by the last-in, first-out method. \$. x c. Determine the inventory cost by the weighted average cost method. Round average unit cost to the nearest cent and final answers to the nearest whole dollar, if required. 4 x Feedback Theck My Work d. Note that this exercise uses the periodic inventory system, FlFo means that the first units purchased are assumed to be the first to