Olsen Outfitters Inc. believes that its optimal capital structure consists of 65% common equity and 35% debt, and its tax rate is 25%. Olsen must raise additional capital to fund its upcoming expansion. The firm will have $4 million of retained earnings with a cost of rs = 10%. New common stock in an amount up to $9 million would have a cost of re = 13.0%. Furthermore, Olsen can raise up to $3 million of debt at an interest rate of rd = 11% and an additional $6 million of debt at rd = 15%. The CFO estimates that a proposed expansion would require an investment of $7.4 million. What is the WACC for the last dollar raised to