I need this properly explained to me step by step.

You have been managing a $3 million portfolio. The portfolio has a beta of 1.10 and a required rate of return of 10%. The current risk-free rate is 5.6%. Assume that you receive another $600,000. If you invest the money in a stock that has a beta of 0.60, what will be the required return on your $3.6 million portfolio?

a. 10.20%

b. 9.67%

c. 9.20%

d. 9.95%

e. 8.75%