A firm's common stock has a beta of $1\mathrm{.}1.$ The risk$-$free rate is $5\mathrm{.}5\%$ and the expected return on the market is $13\%.$ Additionally, the firm has an outstanding bond issuance with $26$ years to maturity trading at $95($par value is $$1,000)$ making semiannual coupon payments at a $6\%$ annual coupon rate.

a$.(9$ pts$.)$ What is the firm's cost of equity?

b$.(9$ pts$.)$ What is the firm's pre$-$tax cost of debt?

c$.(7$ pts$.)$ If the firm's tax rate is $21\%,$ what is the firm's after$-$tax cost of debt?