What is the head of government in Lower Saxony called?

EDITORIAL LEARNING AID

Why is this answer correct?

The head of the state government in Lower Saxony, as in all the large federal states, is called Minister President and is elected by the state parliament. "First Minister" and "Prime Minister" are titles used in other countries, and a mayor heads only a municipality.

Federal state: Minister President. Town: mayor.

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