A firm's stock has a beta of $0\mathrm{.}9$ The expected T$-$bill return is $1\mathrm{.}9\%.$ and the expected market

return is $6\mathrm{.}3\%.$ What cost of equity should the firm use when calculating its WACC?

$7\mathrm{.}57\%$

$3\mathrm{.}96\%$

$8\mathrm{.}22\%$

$5\mathrm{.}86\%$