The correct option is D (c) and (d)
This compound is 1,4−Dichlorobenzene. As, the chlorine is more electronegative atom than the carbon atom so the dipole moment will be towards the chlorine atom. Both chlorines are in the opposite direction and the dipole moment will be canceled out. Hence, it will have overall dipole moment, μ=0
This compound is 1,4−Dicyanobenzene. As, the carbon atom in the cyano group is more electronegative than the carbon atom of the benzene ring so the dipole moment will be towards the Cyano group. So, both Cyano are in the opposite direction and the dipole moment will be canceled out. Hence, it will have overall dipole moment, μ=0
In benzene−1,4−diol and benzene−1,4−dithiol, due to the presence of lone pairs in the oxygen and sulphur atoms, they are aligned in a bent arrangement. Hence, the overall dipole moment will not be canceled out and hence for benzene−1,4−diol and benzene−1,4−dithiol we have μ≠0
Hence, (c) and (d) have non-zero dipole moment.