Bartlett Company's target capital structure is $40\%$ debt, $15\%$ preferred, and $45\%$ common equity. The after$-$tax cost of debt is $6\%,$ the cost of preferred is $7\mathrm{.}50\%,$ and the cost of equity is $12\mathrm{.}75\%.$ The firm will not be issuing any new stock. You were hired as a consultant to help determine their cost of capital. What is its WACC