Sandhill has determined that it could issue $$1,000$ face value bonds with an $9$ percent coupon paid semiannually and a five$-$year maturity at $$900$ per bond. If Sandhill's marginal tax rate is $30$ percent, its after$-$tax cost of debt is closest to:

$8\mathrm{.}2$ percent.

$8\mathrm{.}4$ percent.

$8\mathrm{.}0$ percent.

$8\mathrm{.}6$ percent.