What is the head of government in North Rhine-Westphalia called?

EDITORIAL LEARNING AID

Why is this answer correct?

The head of government of North Rhine-Westphalia 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 a city or municipality.

State of NRW: Minister President. City: mayor.

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