Which federal state is Saxony-Anhalt?

EDITORIAL LEARNING AID

Why is this answer correct?

Saxony-Anhalt lies in the centre of north-eastern Germany between the Harz mountains and the Elbe, bordering Lower Saxony, Brandenburg, Saxony and Thuringia; on the map it bears the number 3. The numbers 1, 2 and 4 stand for other federal states.

Between the Harz and the Elbe, in the middle of Germany: number 3.

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