Which of the following is correct representation of dipole moment of NH₃ molecule? 

The correct option showing the representation of the dipole moment of the NH₃ molecule is:

Step-by-Step Explanation:

1. Understanding Dipole Moment Direction:
A dipole moment vector is conventionally represented by an arrow with a crossed tail ($\mapsto$). The arrow points from the less electronegative atom (positively charged end) towards the more electronegative atom (negatively charged end) or towards the lone pair of electrons.

2. Electronegativity Comparison in N-H Bonds:
In an ammonia (NH₃) molecule, nitrogen (N) is significantly more electronegative than hydrogen (H). Therefore, for each of the three N-H bonds, the bond dipole moment points towards the central nitrogen atom (from H to N).

3. Contribution of the Lone Pair:
Nitrogen has one lone pair of electrons residing in an orbital above the central N atom. The dipole moment contribution from the lone pair acts upwards, pointing away from the nitrogen atom towards the electron pair density.

4. Resultant Dipole Moment (${\mu }_{\text{resultant}}$):
Since the three N-H bond dipoles point upwards towards nitrogen, their vector sum adds constructively in the same upward direction as the lone pair dipole moment.
Consequently, the net or resultant dipole moment (${\mu }_{\text{resultant}}$) of the NH₃ molecule points vertically upwards, giving NH₃ a net dipole moment of about 1.47 D.

5. Analysis of the Image Options:
- All three N-H bond dipoles point upwards toward N.
- The lone pair dipole arrow points upwards away from N.
- The overall resultant dipole moment (${\mu }_{\text{resultant}}$) arrow points upwards, perfectly matching the correct option.