I'm sorry if i'm posting this in the wrong section,i couldn't figure out which section vectors would go in to.

Here is the question :-

A,B and C are the point (0,1,2),(3,2,1) and (1,-1,0) respectively.Find the unit vector perpendicular to the plane ABC.

I've just started learning this topic,and i'm not very strong at it.It'd be great if someone can help me out here.

Thanks.