The following information is extracted from Qiss Company income statement for consecutive three years. Qiss Company Comparative Statement of Financial Performance for the Years Ended December 31, 2015 (RM) 2014 (RM) 2013 (RM) Sales 720,000 600,000 500,000 Cost of goods sold (COGS) 450,000 280,000 250,000 Gross profit 270,000 320.000 250,000 Operating expenses 140,000 110.000 100,000 Net income 130,000 210,000 150,000 Based on common size analysis, analyze the performance of cost of goods sold, gross profit and operating expenses for these three periods. show your workings