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. O a. 10.94% O b. 10.28% O c. 9.62% O d. 10.61% O e. 9.95%