Hemming Co. reported the following current-year purchases and sales for its only product. Required: Hemming uses a perpetual inventory system. Assume that ending inventory is made up of 45 units from the March 14 purchase, 75 units from the July 30 purchase, and all 100 units from the October 28 purchase. Using the specific identification method, calculate the following. a) Cost of Goods Sold using Specific Identification b) Gross Margin using Specific Identification