Periodic Inventory by Three Methods The units of an item available for sale during the year were as follows Jan. 1 Inventory 17 units at $34 Feb 17 Purchase units at $36 Jul 21 Purchase 15 units at $37 Nov. 23 Purchase 4 units at 537 There are 9 units of the item in the physical ptory at December 31. The periodic inventory system is used. Round liverage unit cost to the nearest cent and final answers to the nearest whole dollar if required a. Determine the inventory cost by the first in first out method b. Determine the inventory cost by the last first out method. Determine the inventory cout by the weighted average cost method