Which out of $NH_3$ and $NF_3$ has higher dipole moment and why?

(A) In both molecules,i.e.,$NH_3$ and $NF_3$,the central atom $(N)$ has one lone pair of electrons and three bond pairs. Hence,both molecules have a pyramidal shape.
Since fluorine is more electronegative than hydrogen,it is expected that the net dipole moment of $NF_3$ is greater than $NH_3$. However,the net dipole moment of $NH_3$ $(1.46 \ D)$ is greater than that of $NF_3$ $(0.24 \ D)$.
This can be explained by the directions of the dipole moments of each individual bond in $NF_3$ and $NH_3$.
In $NH_3$,the resultant moment of the three $N-H$ bonds adds up to the bond moment of the lone pair (both are in the same direction).
In $NF_3$,the resultant moment of the three $N-F$ bonds is in the opposite direction to the moment of the lone pair,which partially cancels it out.
Therefore,the net dipole moment of $NH_3$ is higher than that of $NF_3$.