Which of these is a district (Landkreis) in Bavaria?

EDITORIAL LEARNING AID

Why is this answer correct?

The district of Altötting lies in Upper Bavaria and therefore belongs to Bavaria. Prignitz is in Brandenburg, the Rhein-Sieg district in North Rhine-Westphalia and Nordfriesland in Schleswig-Holstein.

Altötting with its pilgrimage chapel is in Upper Bavaria.

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