6. The following information is available for Louisville Limestone Corporation for the current year: Net income $160,000 Preferred dividends 30,000 Interest expense 18,000 Beginning of year: Total assets 900,000 Total liabilities 300,000 Total common shareholders' equity 375,000 End of year: Total assets 950,000 Total liabilities 350,000 Total common shareholders' equity 400,000 The return on assets for Louisville Limestone Corporation is: a. 19.2% b. 19.8% c. 17.3% d. 18.7%