The correct option is A XeOF4
The net dipole moment is zero, if three identical dipole vectors are oriented at 120∘ to each other.
The net dipole moment is zero, if four identical dipole vectors are oriented at 90∘ or 120∘ to each other.
XeF4 is non-polar. It has 4 bond pairs and 2 lone pairs, hence it has a square planar shape. The four dipole moments of the Xe - F bonds cancel out, resulting in zero dipole moment.
SO3 is non polar. It has trigonal planar shape. The dipoles oriented along the 3 S=O bond cancel but each other, resulting in zero dipole moment.
XeOF4 is polar. It has squre pyramidal shape. The O atom is not attached to a F atom, but to the central Xe atom. There is also a lone pair which is attached to Xe the opposite side of O atom. Since there is not an odd number of atoms, attached to the central Xe, the dipoles do not cancel out and molecule is polar.
ICl−4 is non- polar because it has square planar geometry. All dipole from Cl cancel each other.