Which federal state is Rhineland-Palatinate?

EDITORIAL LEARNING AID

Why is this answer correct?

On the map for this question, Rhineland-Palatinate is marked with the number 1; the state lies in the south-west of Germany and borders France, Luxembourg and Belgium. The other numbers designate other federal states and are therefore wrong.

Rhineland-Palatinate: south-west, bordering France and Luxembourg.

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