The units of Manganese Plus available for sale during the year were as follows: Mar. 1 June 16 $638 Inventory Purchase Purchase 22 units 30 units @ $29 @ $31 930 Nov. 28 @ $38 1,596 42 units 94 units $3,164 There are 14 units of the product in the physical inventory at November 30. The periodic inventory system is used. Round answers to the nearest whole dollar a. Determine the inventory cost by the FIFO method. b. Determine the inventory cost by the LIFO method. c. Determine the inventory cost by the average cost methods