The units of an item available for sale during the year were as follows:

Jan. 1 Inventory 27 units at $120

Feb 17 purchase 54 units at $138

July 21 purchase 63 units at $156

Nov 23 purchase 36 units at $165

there are 50 units of the item in the physical inventory at Dec 31. The periodic inventroy system is used. Determine the inventory cost by (a) the first-in, first-out method, (b) the last-in, first-out, and (c) the average cost method.