The Market Value of Fortescue's Ordinary Shares, Preference Shares and Debt

The market value of Fortescue's ordinary shares, preference shares and debt are $7 billion, $3 billion, and $10 billion, respectively. Fortescue has a beta of 1.8, the market risk premium is 7%, and the risk-free rate of interest is 4%. Fortescue's preference shares pays a dividend of $3.5 each year and trades at a price of $27 per share. Fortescue's debt trades with a yield to maturity of 9.5%. What is Fortescue's weighted average cost of capital if its tax rate is 30%?

A) 11.08%
B) 11.47%
C) 10.34%
D) 10.12%