When does the statutory night-time rest period begin in Germany?

EDITORIAL LEARNING AID

Why is this answer correct?

The statutory night rest period in Germany begins at 10 p.m. and usually ends at 6 a.m.; during this time loud noises such as making music or drilling must be avoided. Sunset (a), the neighbours' bedtime (b) and midnight (c) are not the legal boundaries.

Night rest from 10 p.m. to 6 a.m. – keep quiet then.

This translation and explanation are editorial learning aids. The official German wording and answer key govern the examination.