\fCarla Vista Medical Comparative Income Statement and Statement of Retained Earnings For the Year 2020 2019 Sales revenue {all on account] $10.177.200 $9,613,900 Cost of goods sold 5.611.750 5,298,203 Gross prot 4.565.450 4,315,200 Operating expenses 2.340.300 2,634,100 Net operatingincome 1.725.150 1,681,100 Interest expe nse 300.300 308,650 Net income before taxes 1.424.850 1,372,450 Income taxes [30%) 427.455 411,235 Net income 3997.395 $960,215 Dividends paid Preferred dividends 29.550 29,550 Common dividends 433.350 413,100 Total dividends paid 462.900 442,650 Net income retained 534.545 513,065 Retained earnings. beginning of year 3.660.465 3,142,400 Retained earnings.encl of year $4.195.010 $3,660,465 Calculate the Fol lowing protability ratios for 2020. [Round answers to 1 decimalpl'aoe, as. 50196.] a. Gross margin percentage b. Return on assets c Return on common stockholders' equity.r l %