Green Carpet Co. is estimated to have a total capital of $60 million, with $30 million in long-term debt and 30 million in common equity. The firm's present capital structure is considered to be optimal. The company plans to raise $30 million to finance new projects. For the required capital, new bonds will have an 8% coupon rate, and they will be sold at par. The common stockholders' required rate of return is estimated to be 12%. Assume the marginal tax rate is 25% a. How much of the new investment must be financed by common equity to maintain the optimal capital structure? b. To maintain its target capital structure, what is its WACC? c. The company has two options to raise the capital from the equity market: 1 . using retained earnings; 2 . issuing additional shares of common equity. Discuss qualitatively how the two options would impact the WACC