Last year Vaughn Corp. had sales of $315,000 and a net income of $17,832, and its year-end assets were $210,000. The firm's total-debt-to-total-assets ratio was 20%. Based on the DuPont equation, what was Vaughn's ROE? Select the correct answer. a. 10.8496 b. 11.07% c. 11.30% d. 10.6196 e. 10.389