Mojo Mining has a bond outstanding that sells for $$2,174$ and matures in $18$ years. The bond pays semiannual coupons and has a coupon rate of $7\mathrm{.}14$ percent. The par value is $$2,000.$ If the company's tax rate is $21$ percent, what is the aftertax cost of debt?

Multiple Choice

$5\mathrm{.}00\%$

$4\mathrm{.}13\%$

$6\mathrm{.}51\%$

$6\mathrm{.}07\%$

$3\mathrm{.}60\%$