Allison Engines Corporation has established a target capital structure of 40 percent debt and 60 percent common equity. The firm expects to earn $600 in after-tax income during the coming year, and it will retain 40 percent of those earnings. The current market price of the firm's stock is P₀ = $28; its last dividend was D₀ = $2.20, and its expected dividend growth rate is 6 percent. Allison can issue new common stock at a 15 percent flotation cost. What will Allison's marginal cost of equity capital (not the WACC) be if it must fund a capital budget requiring $600 in total new capital?

a. 13.9%

b. 15.8%

c. 14.3%

d. 9.7%

e. 7.9%