The units of Manganese Plus available for sale during the year were as follows: Mar. 1 Inventory 20 units @ $31 June 16 Purchase 28 units @ $32 Nov. 28 Purchase 38 units @ $38 86 units $620 896 1,444 $2,960 There are 15 units of the product in the physical inventory at November 30. The periodic inventory system is used. a. Determine the inventory cost using the FIFO method. b. Determine the inventory cost using the LIFO method. c. Determine the inventory cost using the weighted average cost methods. Round interim calculations and final answer to two decimal places.