Why is the staA common size income statement analysis would show what figure for the following company: 2016 2015 Net sales $668,450 $641,712 Cost of goods sold $200,000 $224,000 Gross margin $468,450 $417,712 Selling/administrative costs $120,000 $125,000 Operating income $348,450 $292,712 Income tax expense $66,206 $55,615 Net income $282,244 $237,097 a. The 2016 change in operating income is $55,738 b. 2016 operating income (as a percent of net sales) is 52.1% c. The percent change in net income is 19% or D. The change in gross margin is $50,738tement of cash flows necessary?