Gladstone Company tracks the number of units purchased and sold throughout each accounting period but applies its inventory costing method at the end of each period, as if it uses a periodic inventory system. Assume its accounting records provided the following information at the end of the annual accounting period, December 31. Transactions Beginning inventory, January 1 Transactions during the year: a. Purchase, January 30 Units 1,800 Unit Cost $50 b. Sale, March 14 ($100 each) c. Purchase, May 1 d. Sale, August 31 ($100 each) Required: 2,500 62 (1,450) 1,200 80 (1,900) Compute the amount of goods available for sale, ending inventory, and cost of goods sold at December 31 under each of the following inventory costing methods: Last-in, first-out.