Rogers Products uses a periodic inventory system. The company's records show the beginning inventory of PH4 oil filters on January 1 and the purchases of this item during the current year to be as follows Beginning inventory Jan. 1 Feb. 23 Purchase Apr. 20 Purchase May 4 Nov. 30 Purchase 13 units $3.00 39.00 52.50 106.40 37 units $4.00 148.00 100.00 445.90 15 units $3.50 28 units e $3.80 Purchase 20 units $5.00 Totals 113 units A physical count indicates 21 units in inventory at year-end Determine the cost of the ending inventory on the basis of each of the following methods of inventory valuation. (Remember to use periodic inventory costing procedures.) (Round your intermediate and final answers to 2 decimal places.) Ending Inventory a. Average cost b. FIFO C. LIFO