A firm has 10 million shares of common stock outstanding. The stock sells for $52.00 each. The stock just paid a dividend of $1 per share and has a dividend growth rate of 3.40%. The firm also has 500,000 bonds outstanding, with a face value of $1,000 each, a 10 -year maturity and a 6.40% coupon (payable semiannually). The bonds sell for 86% of face value. Finally, the firm has 7 million shares of 5% preferred stock outstanding which currently sell for $70.00 each and have a par value of $80. The firm pays at a corporate income tax rate of 35%. What is the firm's WACC? a. 5.54% b. 6.43% c. 7.72% d. 3.98% e. 4.78%