Following is financial statement information for Rogex Corporation; cash =$242; accounts receivable = $850; inventory = $820; net fixed assets =$3,408; accounts payable =$700; short-term notes payable = $740; long-term liabilities =$1,100; common stock = $1,160; retained earnings =$1,620; net sales =$2,768; cost of goods sold =$1,210; depreciation =$360; interest expense =$160; taxes =$312; addition to retained earnings =$508; and dividends paid =$218. What is Rogex's return on total assets? a. 37.9% b. 9.6% c. 13.6% d. 19.1%