Delta Corporation has the following capital structure: Debt (Kd) Preferred stock (Kp) Common equity (Ke) (retained earnings) Weighted average cost of capital (Ka) Cost (aftertax) Weights 6.1% 25% 7.6 10 15.1 65 Weighted Cost 1.53% 0.76 9.82 12.10% a. If the firm has $26 million in retained earnings, at what size capital structure will the firm run out of retained earnings? (Enter your answer in millions of dollars (e.g., $10 million should be entered as "10").) Capital structure size (X) million b. The 6.1 percent cost of debt referred to earlier applies only to the first $13 million of debt. After that the cost of debt will go up. At what size capital structure will there be a change in the cost of debt? (Enter your answer in millions of dollars (e.g., $10 million should be entered as "10").) Capital structure size (Z) million