The following information is taken from company A's books: Income statement for the year ended: Sales revenue Cost of sales Gross profit Operating expenses Operating income Interest expense Pre-tax income Income tax expense 12.31.2019 12.31.2020 $1,000,000 $1,200,000 700,000 720,000 300,000 480,000 150,000 180,000 150,000 300,000 30,000 60,000 120,000 240,000 42,000 84,000 Net Income $ 78,000 $ 156,000 Balance sheet as of: 12.31.2018 12.31.2019 12.31.2020 Assets: Cash 50,000 100,000 130,000 Accounts receivable 160,000 250,000 270,000 Inventory 50,000 60,000 65,000 Total current assets 260,000 410,000 465,000 Property, plant and equipment, net 480,000 500,000 550,000 Total assets 740,000 910,000 1,015,000 Liabilities and stockholders equity: Liabilities: Current liabilities: Accounts payable 25,000 38,800 50,000 Unearned revenue 36,000 37,400 52,000 Total current liabilities 61,000 76,200 102,000 Long term debt 342,000 400,000 420,000 Total Liabilities 403,000 476,200 522,000 Stockholders equity: Common stock at par 1,000 1,000 1,000 Additional paid in capital 200,000 200,000 200,000 Retained earnings 141,000 240,000 300,000 Treasury stock (5.000) (7.200) (8.000) Total liabilities and stockholders equity 740,000 910,000 1,015,000 Company A's return on assets during 2020 changed as follows: Select one: a. The profit margin significantly increased and the asset turnover remained relatively constant so the return on assets increased b. The profit margin significantly increased and the asset turnover significantly decreased but the return on assets remained the same c. Both the profit margin and the asset turnover significantly increased so the return on assets increased d. The profit margin significantly decreased and the asset turnover significantly increased but the return on assets remained the same