Let $x+y+3z-4=0,x+2y+bz-5=0$ and $2x+ay+6z-8=0$ be three planes, then

three planes intersect at a point if $a\ne 2,b\ne 3$

three planes do not have any common point of intersection if $a\ne 2,b=3$

three planes have infinite points common among them if $a=2,b\in R$

three planes never intersect at exactly two distinct points