The units of an item available for sale during the year were as follows: There are 13 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. x b. Determine the inventory cost by the last-in, first-out method. \& 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