Suppose that over the last 20 years, company XYZ has averaged a return of 13.0%. Over the same period, the Treasury bill rate has averaged 4.0%. The Current estimate of the Treasury bill rate is 7.5%. Using the historical approach, what is the estimate of XYZ's current expected return? a. 20.5% b. 15.5% c. 11.5% d. 16.5%