WB Inc. is funded by common & preferred equity and long$-$term debt and is subject to a $21\%$ tax rate. Its common equity comprises $40\%$ of its capital structure, while its preferred equity makes up $10\%$ and debt is the remaining $50\%$ of capital. The equity market commands a risk premium of $8\%,$ and WB$$s beta is $1\mathrm{.}2.$ WB$$s preferred shares cost $$50$ and pay a $$5$ annual dividend. Its long$-$term $$1,000$ bonds sell at par value and pay a $$50$ annual dividend semi$-$annually, in an environment where the risk free rate is $2\mathrm{.}5\%.$

a$.$ What is WB$$s cost of common equity?

b$.$ What is WB$$s cost of preferred equity?

c$.$ What is WB$$s cost of debt?

d$.$ What is WB$$s WACC?