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 10%. Based on the DuPont equation, what was Vaughn's ROE? Select the correct answer. a. 9.95% b. 10.99% c. 9.43% d. 11.51% e. 10.47%