Problem $7$:

The figure below shows forces acting at various points on a metal bar. The angles $=46,=35,=23.$ The length of this bar is $t=3\mathrm{.}8m.$

Find the magnitude of the net torque $($in $m*N)$ on this bar about an axis through point O perpendicular to the page. $($Point $O$ is depicted in this figure.$)$

$($A$)65$ mN

$($B$)58$ mN

$($C$)42$ mN

$($D$)37$ mN

$($E$)24$ mN