Periodic inventory using FFO, UFO, and weighteo average cost methods The units of an item avaliable for sale during the year were as follows: There are 18 units of the item in the physical ioventory at December 31. The periodic inventory system is used. Determine the inventory cost using the (a) fint-in, first-out (FIF) method; (t (c) weighted average cost method (round per-unit cost to two decimal places and your final answer to the nearest whole dollar). a. First-in, first-out (Prifo) method b. Last-in, fint-out (LFF) mettod c Weighted average cost method