Which of following has highest dipole moment

In given all molecules, only ${\text{NH}}_3$ and ${\text{H}}_{\text{2}}\text{O}$ show dipole moment whereas HI and ${\text{SO}}_3$ does not show. Because there are no hydrogen atoms in ${\text{SO}}_3$ molecule. Hence, hydrogen bonding does not exist in ${\text{SO}}_3$. In HI, the electro negativity difference between hydrogen, H and iodine, I is low. So, hydrogen bonding does not exist in HI. The dipole moment of ${\text{H}}_{\text{2}}\text{O}$ is more ${\text{NH}}_3$. Since the E.N  of  oxygen ,O is high than E.N of Nitrogen, N.