The units of an item available for sale during the year were as follows: Jan. 1 Inventory 50 units at $115 Feb. 17 Purchase 88 units at $140 July 21 Purchase 35 units at $128 Nov. 23 Purchase 15 units at $155 There are 75 units of the item in the physical inventory at December 31. The periodic inventory system is used. Determine the inventory cost by (a) the first-in, first-out method, (b) the last-in, first-out method, and (c) the average cost method.