You are estimating the WACC for Noble Inc. You found on Noble Inc's Balance Sheet that the company has no short-term debt but it has $20 million in long-term debt. In addition, its market cap is $80 million. Currently, a long-term bond issued by Noble Inc. is traded at a yield-to-maturity of 5%. In addition, you observe that its stock beta is 1.5, the 10-year Treasury yield is 4%, and you have decided that the current equity market risk premium is 4%. Assuming that the company's marginal tax rate is 30%, you estimate that Noble Inc.'s WACC is closest to _______.

a. 8.7%

b. 9.0%

c. 6.6%

d. 6.2%