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 62.5%. Based on the DuPont equation, what was Vaughn's ROE?

a. 22.27%

b. 23.38%

c. 22.64%

d. 23.01%

e. 23.75%