A bond with a $4\%$ coupon is priced at a $3\mathrm{.}20$ basis. If the bond's yield$-$tomaturity decreased by $10$ basis points, the yield would be:

A $3\mathrm{.}90\%$

B

$3\mathrm{.}30\%$

$4\mathrm{.}10\%$

$3\mathrm{.}10\%$