Kroncke Company, whose target capital structure is $50\%$ debt, $11\%$ preferred, and $39\%$ common equity. The after$-$tax cost of debt is $4\mathrm{.}50\%,$ the cost of preferred is $6\mathrm{.}50\%,$ and the cost of retained earnings is $14\mathrm{.}00\%.$ The firm will not be issuing any new stock. What is its WACC?

a$.$

$7\mathrm{.}75\%$

b$.$

$8\mathrm{.}43\%$

c$.$

$8\mathrm{.}33\%$

d$.$

$9\mathrm{.}05\%$