QII WOTF is $/$ wrrect.

$($a$)$ If vec$(n)*vec(a)=0$;vec$(n)*vec(b)=0$;vec$(n)*vec(c)=0$ for some non$-$zero victor vec$(n)$ then scalar product of $a,b,0$ is $0.$

$($b$)$ There exist a weitos making angles $30$&$45$ with $x-$anis & $y-$anis respe.

$($c$)$ lows of point for which $x=3$ & $y=4$ is a line paralle to $z-$axis nehose distance from $z-$anis is $5,$

$($d$)$ the vertices of a regular tetrahedron are $O,A,B,C$ where $O$ is origin. The vector vec$(DA)+$Ovec$(B)+$Ovec$(C)$ is $1^r$ to the plane ABC.