ABC Co$.$ issues $$1,000$ par value, $6\mathrm{.}5\%$ semiannual coupon bonds, with $15$ years to maturity. The company sells the bonds for $$750.$ Find the after$-$tax cost of debt assuming a tax rate of $35\%.$

$3\mathrm{.}05\%$

$4\mathrm{.}85\%$

$5\mathrm{.}65\%$

$6\mathrm{.}31\%$