Allison Engines Corporation has established a target capital structure of 40 percent debt and 60 percent common equity. The current market price of the firm's stock is PO = $34.6; its last dividend was DO = $2.2, and its expected dividend growth rate is 7 percent. What will Allison's marginal cost of retained earnings.rs, be? 14.30% 13.30% 12.80% 13.80% 14.80%