Assume that the market value of J Ho Company's total debt is $$725,000$ and its total equity is $$275,000.$ The marginal corporate tax rate is $21\%.$ If the before$-$tax cost of debt is $5\mathrm{.}4\%$ and the cost of equity is $8\mathrm{.}8\%,$ what is the cost of capital $($WACC$)$ for this company?

$6\mathrm{.}34\%$

$5\mathrm{.}51\%$

$7\mathrm{.}87\%$