Baxter Inc. Has a target capital structure of 30% debt, 15% preferred stock, and 55% common equity. The company's after-tax cost of debt is 7%, it's cost of preferred stock is 11%, it's cost of retained earnings is 15%, and it's cost of new common stock is 16%. The company stock has a beta of 1.5 and the company's marginal tax rate is 35%. What is the company's weighted average cost of capital if retained earnings are used to fund the common equity portion?

A. 11.20

B. 12.00

C. 13.80

D. 14.45