I'm struggling a lot with specific identification and need an explanation as to HOW you get the numbers

2. Gladstone Limited 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. 10 points Units 1,900 Unit Cost $ 4.00 Transactions Beginning inventory, January 1 Transactions during the year: Purchase, January 30 b. Sale, March 14 $10 each) Purchase, May 1 d. Sale, August 31 ($10 each) a. 6.00 eBook 2,500 (1,500) 1,200 (1,900) 8.00 Print References Required: 1. 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. For Specific identification, assuming that the March 14, sale was selected two-fifths from the beginning inventory and three-fifths from the purchase of January 30. Assume that the sale of August 31, was selected from the remainder of the beginning inventory, with the balance from the purchase of May 1. (Do not round Weighted average cost per unit. Round your final answers to the nearest dollar amount.) Ending inventory Cost of goods sold Goods available for sale $ 32,200 $ 32,200 $ 32,200 $ 27,236 $ a. Weighted average cost. b. First-in, first-out. Specific identification. 42,092 2-a. Of the three methods, which will result in the highest gross profit? Weighted average cost O First-in, first-out O Specific identification 2-b. Of the three methods, which will result in the lowest income taxes? Weighted average cost First-in, first-out O Specific identification