The units of Manganese Plus available for sale during the year were as follows: Mar. 1 June 16 Nov. 28 Inventory Purchase Purchase 23 units @ $30 $690 28 units @ $35 980 38 units @ $39 1,482 89 units $3,152 There are 18 units of the product in the physical inventory at November 30. The periodic inventory system is used. 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. Round answer to two decimal places. $