Sorensen Systems Inc. is expected to pay a $3.30 dividend at year end (D1 = $3.30), the dividend is expected to grow at a constant rate of 6.00% a year, and the common stock currently sells for $72.50 a share. The before-tax cost of debt is 7.00%, and the tax rate is 25%. The target capital structure consists of 45% debt and 55% common equity. What is the company's WACC if all the equity used is from retained earnings? Do not round your intermediate calculations. O a. 8.32% b. 7.90% O c. 8.17% d. 6.72% e. 7.64%