Tony's Corporation's stock had a required return of 7.90% last year when the risk-free rate was 2.50% and the market risk premium was 4.50%. Then an increase in investor risk aversion caused the market risk premium to rise by 1% from 4.5% to 5.5%. The risk-free rate and the firm's beta remain unchanged. What is the company's new required rate of return?

a. 8.50%

b. 8.88%

c. 9.10%

d. 9.54%

e. 9.98%