Which coat of arms belongs to the federal state of Rhineland-Palatinate?

EDITORIAL LEARNING AID

Why is this answer correct?

The state coat of arms of Rhineland-Palatinate combines, in three fields, the wheel of Mainz, the cross of Trier and the Palatine lion; picture 1 shows this coat of arms. Pictures 2, 3 and 4 show the coats of arms of other federal states and are therefore wrong.

Wheel, cross, lion – Mainz, Trier, Palatinate.

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