What are the colours of the state flag of Lower Saxony?

EDITORIAL LEARNING AID

Why is this answer correct?

The state flag of Lower Saxony is black-red-gold and shows the white Saxon horse in the centre. White-blue is the flag of Bavaria, black-yellow the flag of Baden-Württemberg and blue-white-red the flag of Schleswig-Holstein.

Black-red-gold with a white horse – Lower Saxony.

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