Let $A=\{3,6,9,12\}$ and $R=\{(3,3),(6,6),(9,9),(12,12),(6,12),(3,9),(3,12),(3,6)\}$ be a relation on the set $A$. The relation is:

1. Reflexive: A relation is reflexive if for every $a\in A$, $(a,a)\in R$. Here, $(3,3),(6,6),(9,9),(12,12)\in R$. So, it is reflexive.2. Symmetric: A relation is symmetric if $(a,b)\in R⟹(b,a)\in R$. Here, $(6,12)\in R$ but $(12,6)\notin R$. So, it is not symmetric.3. Transitive: A relation is transitive if $(a,b)\in R$ and $(b,c)\in R⟹(a,c)\in R$.For $(3,6)$ and $(6,12)$, we have $(3,12)\in R$.Checking all pairs, we find it satisfies transitivity.Hence, the relation is reflexive and transitive only.