Which of the following compound(s) is/ are planar about nitrogen?

$\mathrm{N}{\left({\mathrm{SiH}}_3\right)}_3$ is planar because in $\mathrm{N}{\left({\mathrm{SiH}}_3\right)}_3$ lone pair on N−atom is shifted to the blank d− orbitals of silicon (pπ−dπ overlapping).

In $\mathrm{N}{\left({\mathrm{SiH}}_3\right)}_3$​, Si has vacant d-orbital. Here, the dπ−pπ overlap along the N−Si bond.

Thus, nitrogen has trigonal planar shape.

${\mathrm{NBF}}_{23}$ is also planer about nitrogen atom.