Olsen Outfitters Inc. believes that its optimal capital structure consists of 70% common equity and 30% debt, and its tax rate is 40%. Olsen must raise additional capital to fund its upcoming expansion. The firm will have $3 million of retained earnings with a cost of rs = 12%. New common stock in an amount up to $7 million would have a cost of re = 15%. Furthermore, Olsen can raise up to $4 million of debt at an interest rate of rd = 11%, and an additional $5 million of debt at rd = 12%. The CFO estimates that a proposed expansion would require an investment of $9.5 million. What is the WACC for the last dollar raised to complete the expansion?