Which body is not one of Germany's constitutional organs?

EDITORIAL LEARNING AID

Why is this answer correct?

The constitutional organs are the Bundestag, the Bundesrat, the Federal Government, the Federal President and the Federal Constitutional Court. A citizens' assembly is not a constitutional organ but a meeting of citizens.

Constitutional organs: Bundestag, Bundesrat, government, president, Constitutional Court.

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