1a. Assuming the use of a periodic inventory system, compute Cost of Goods Sold under each method of inventory: average cost, FIFO, LIFO, and specific identification. For specific identification, assume that the first sale was selected from the beginning inventory and the second sale was selected from the January 12 purchase. 1b. Assuming the use of a periodic inventory system, prepare a partial income statement under each method of inventory: (a) average cost, (b) FIFO, (c) LIFO, and (d) specific identification. For specific identification, assume that the first sale was selected from the beginning inventory and the second sale was selected from the January 12 purchase.