(A) SO3 :
(B) NF3 :
(C) NH3 :
(D) N(SiH3)3 :
Due to delocalization of lone pair of Nitrogen with vacant d-orbital of Si.Cause, the molecule become planer. that's why \(\mu= 0\).
NH3 has maximum dipole moment. NF3 and NH3 both molecule have Pyramidal shape with lone pair of electron on nitrogen atom.There is a greater electronegative difference on nitrogen atom.
There is a greater electronegative difference between N and H atom than N and F atom. In NH3, the orbital dipole due to lone pair is in the same direction. while in the opposite directions. that's why. NH3 has more dipole moment than NF3.