Which compound exhibits the maximum dipole moment among the following?

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 :-

Number of compounds from the following with zero dipole moment is . . . . . .
$HF, H_2, H_2S, CO_2, NH_3, BF_3, CH_4, CHCl_3, SiF_4, H_2O, BeF_2$

Which of the following is a polar molecule?

Which of the following compounds is polar?

Which of the following molecules has the largest dipole moment?