The following information is taken from the records of four different companies in the same in- dustry: Sales Opening Inventory Purchases Cost of Goods Available for Sale Ending Inventory Cost of Goods Sold Gross Profit Gross Profit percentage A $300 ? 240 320 ? ? $100 ? B $150 40 ? ? (60) 100 $ ? $ ? 40 ? 190 (60) 130 $ 65 ? D $ 90 12 63 ? (15) 60 $ ? ? ? Required: a. Calculate the missing amounts. b. Which company seems to be performing best? Why