Ochem Chapter 1 Passage IV Question 24

Formamide / Methanamide is a fully planar molecule.
D, "The six atoms are coplanar" means they are all in the same plane. Similar to aromatics or benzene.

A says, "The nitrogen has trigonal pyramidal geometry, so the two hydrogens are outside of the plane created by the other four atoms."

The reason the hydrogens are in the same plane as the carbonyl is for resonance delocalization and stability of amides.
The lone pair can move between the C-N bond, allowing the carbonyl to shift electrons to make the oxygen negative (O-).

 

So the nitrogen isn't truly sp3 hybridized is it? The delocalized lone pair suggests this to me.