The units of Manganese Plus available for sale during the year were as follows: $30 Mar. 1 June 16 Nov. 28 Inventory Purchase Purchase $660 990 22 units 30 units 43 units 95 units $33 $38 1,634 $3,284 There are 17 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