Williamson, Inc., has a debt$-$equity ratio of $2\mathrm{.}44.$ The company's weighted average cost of capital is $9$ percent, and its pretax cost of debt is $7$ percent. The corporate tax rate is $21$ percent.$$a$.$What is the company's cost of equity capital? $($Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$b$.$What is the company's unlevered cost of equity capital? $($Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$c$.$What would the weighted average cost of capital be if the company's debt$-$equity ratio were $\mathrm{.}60$ and $1\mathrm{.}75?($Do not round intermediate calculations and enter your answers as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$