Unit of dipole moment is:

CONCEPT: 

• Electric dipole: When two equal and opposite charges are separated by a small distance then this combination of charges is called an electric dipole.
  • The multiplication of charge and the distance between them is called an electric dipole moment.
  • The electric dipole moment is denoted by P and the SI unit of dipole moment is Coulombmeter (Cm)

Dipole moment (p) = q × d

Where q is charge and d is the distance between two charged particles.

• The direction electric dipole moment is from a negative charge to a positive charge.

EXPLANATION:

• From the above, it is clear that the unit of dipole moment is coulombmeter (Cm). Therefore option 2 is correct.