The flow rate in a rectangular channel $6$ m across is $24\frac{m^3}{s}.$ At critical flow, the velocity

is most nearly

$($A$)$

$1\mathrm{.}1\frac{m}{s}$

$($B$)$

$3\mathrm{.}4\frac{m}{s}$

$($C$)6\mathrm{.}3\frac{m}{s}$

$($D$)$

$14\frac{m}{s}$