Electronic Products has $22,500$ bonids outstaniding that are currently quoted at $101\mathrm{.}6.$ The bonds thature in $8$ years and pay ain aninual coupori paytrent of sot. What is the firm's aftertax cost of debt if the applicable tax rate is $21$ percent?

$5\mathrm{.}47\%$

$4\mathrm{.}79\%$

$5\mathrm{.}75\%$

$6\mathrm{.}89\%$

$6\mathrm{.}67\%$