You were hired as a consultant to Giambono Company, whose target capital structure is 40% debt, 15% preferred, and 45% common equity. The after-tax cost of debt is 6.00%, the cost of preferred is 7.50%, and the cost of retained earnings is 12.75%. The firm will not be issuing any new stock. What is its WACC?

a. 8.98%

b. 9.26%

c. 9.54%

d. 9.83%

e. 10.12%

Please provide breakdown as to how the answer was arrived at. I need the actual formula and then calculation. Thank you.