In which places does the European Parliament work?

EDITORIAL LEARNING AID

Why is this answer correct?

The European Parliament works in Strasbourg, Luxembourg and Brussels: the plenary meets in Strasbourg, committee meetings are held in Brussels, and the administration is based in Luxembourg. The other cities are not places where the parliament works.

Parliament: Strasbourg, Brussels, Luxembourg.

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