The order of dipole moments of the following molecules is

Statement $I$: Dipole moment is a vector quantity and by convention it is depicted by a small arrow with tail on the positive centre and head pointing towards the negative centre.
Statement $II$: The crossed arrow of the dipole moment symbolizes the direction of the shift of charges in the molecules.
In the light of the above statements,choose the most appropriate answer from the options given below :-

Which one of the following molecules has the maximum dipole moment?

The observed dipole moment of $HCl$ is $1.303 \ D$. This indicates that $HCl$ has $17 \%$ ionic and $83 \%$ covalent character. The bond length of $HCl$ is $1.26 \ \mathring{A}$ and the charges on $H$ and $Cl$ ions are $+e$ and $-e$. Calculate the theoretical dipole moment in $D$.

The critical temperature of water is higher than that of $O_2$ because $H_2O$ molecules have ......

Which of the following compounds has the least dipole moment?