Answer: $D$
Take $(3, 6)$ and $(6, 2)$ elements of $R$. For transitivity $(3, 2)$ must be element of $R$, but $3$ and $2$ don't have a common divisor and hence not in $R$.
For any positive integer $n$, $(n, n)$ is not element of $R$ as only distinct $m$ and $n$ are allowed for $(m, n)$ in $R$. So, not reflexive also.