Oriole Medical manufactures hospital beds and other institutional furniture. The company's comparative balance she statement for 2019 and 2020 follow. Oriole Medical Comparative Balance Sheet As of December 31 2020 2019 Assets Current assets Cash $398,000 $417,450 Accounts receivable, net 1,046,000 776,450 Inventory 730,000 681,050 Other current assets 381,300 247,100 Total current assets 2,555,300 2,122,050 Property, plant, & equipment, net 8,711,250 8,439,765 Total assets $11,266,550 $10,561,815 Liabilities and Stockholders' Equity Current liabilities $3,206,000 $2,846,050 Long-term debt 3,702,650 3,892,600 Total liabilities 6,908,650 6,738,650 Preferred stock, $5 par value 59,000 59,000 Common stock, $0.25 par value 104,650 103,800 Retained earnings 4,194,250 3,660,365 Total stockholders' equity 4,357,900 3,823,165 Total liabilities and stockholders' equity $11,266,550 $10,561,815 Oriole Medical Comparative Income Statement and Statement of Retained Earnings For the Year Sales revenue (all on account) Cost of goods sold 2020 2019 $10,177,200 $9,613,900 5,612,550 5,298,700 Gross profit 4,564,650 4,315,200 Operating expenses 2,840,300 2,634,100 Net operating income 1,724,350 1,681,100 Interest expense 300,300 308,650 Net income before taxes 1,424,050 1,372,450 Income taxes (30%) 427,215 411,735 Net income $996,835 $960,715 Dividends paid Preferred dividends 29,550 29,550 Common dividends 433,400 413,100 Total dividends paid 462,950 442,650 Net income retained 533,885 518,065 Retained earnings, beginning of year 3,660,365 3,142,300 Retained earnings, end of year $4,194,250 $3,660,365 Calculate the following profitability ratios for 2020. (Round answers to 1 decimal place, e.g. 50.1%.) a. Gross margin percentage b. Return on assets % % % C. Return on common stockholders' equity