The units of Manganese Plus available for sale during the year were as follows: $713 Mar. 1 June 16 Inventory Purchase 23 units 30 units @ $31 @ $34 1,020 Nov. 28 Purchase 40 units @ $36 1,440 93 units $3,173 There are 16 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