Pemberton Products uses a periodic inventory system. The company's records show the beginning inventory of PH4 oil filters on January I and the purchases of this item during the current year to be as follows: Jan. Feb. 23 1 Beginning inventory Purchase Apr. 20 Purchase May 4 Purchase Nov. 30 Purchase Totals $ 27.00 9 units @ $3.00 12 units $3.50 30 units @ $3.80 40 units $4.00 42.00 114.00 160.00 19 units @$5.00 95.00 110 units $438.00 A physical count indicates 20 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.) a. Average cost b. FIFO c. LIFO