Let A $=1$i$+$ij$-2$kB$=2$i$-$j$+3$kC $=$ j$-5$kLet $"$O$"$ be the tail of B and let A be a force acting at the head of B$\mathrm{.}1)$ Find the torque of A about $"$O$"2)$Find the torque about a line through O perpendicular to the plane of A and B$3)$ Find the torque about a line through O parallel to C$.$thank you