Chemical Bonding And Molecular Structure

Consider the following

Assertion (A) Dipole moment of $\mathrm{NF}_3$ is lesser than $\mathrm{NH}_3$.

Reason (R) In $\mathrm{NF}_3$, the orbital dipole due to lone pair of electrons is in the opposite direction to the resultant dipole moment of the three $\mathrm{N}-\mathrm{F}$ bonds.

The correct answer is