On the set ' N ' of all natural numbers, define the relation ' R ' by aRb if the G.C.D of a and b is 2.  Then R is

GCD of (3,3)=3R is not reflexive If (a,b)∈R⇒GCD of (a,b)=2 then GCD of (b,a)=2 R is symmetrica,b,(b,c)∈Rbut a,c∉R  ∵8,10,10,12∈R but 8,12∉RR is not transitive