Your firm has a target debt ratio of 30%. Cost of debt (RB) is 6%. The risk-free rate is 3% and the expected market risk premium is 6%. Your firm's unlevered (asset) beta is 1. What is the appropriate rate to discount the interest tax shields associated with your debt? \begin{tabular}{c} \hline 10.00% \\ \hline 11.57% \\ \hline 6.00% \\ \hline 9.00% \\ \hline 4.00% \end{tabular}