The units of Manganese Plus available for sale during the year were as follows: Mar. 1 $651 Inventory Purchase $31 $33 June 16 21 units 33 units 37 units 91 units Nov. 28 Purchase $36 1,089 1,332 $3,072 There are 12 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