Which of these is a district (Landkreis) in Mecklenburg-Vorpommern?

EDITORIAL LEARNING AID

Why is this answer correct?

The Mecklenburg Lake District is the largest district in Mecklenburg-Vorpommern. The Prignitz lies in Brandenburg, the Vogtlandkreis in Saxony and the Rhein-Sieg-Kreis in North Rhine-Westphalia.

Seenplatte is in MV; Vogtland in Saxony, Prignitz in Brandenburg.

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