Kirtland Corporation uses a periodic inventory system. At the end of the annual accounting period, December 31, the accounting records for the most popular item in inventory showed the following: Units 420 Unit Cost $5.00 Transactions Beginning inventory, January 1 Transactions during the year: a. Purchase, January 30 b. Purchase, May 1 Sale ($7 each) d. Sale ($7 each) 3.60 6.00 320 480 (180) (720) Required: a. Compute the amount of goods available for sale. b.& c. Compute the amount of ending inventory and cost of goods sold at December 31, under Average cost, First-in, first-out, Last-in, first-out and Specific identification inventory costing methods. For Specific identification, assume that the first sale was selected two- fifths from the beginning inventory and three-fifths from the purchase of January 30. Assume that the second sale was selected from the remainder of the beginning inventory, with the balance from the purchase of May 1