Which country was not an "Allied occupying power" in Germany?

EDITORIAL LEARNING AID

Why is this answer correct?

Japan was not an Allied power but an ally of Germany and was itself occupied by the USA. The USA, the Soviet Union and France, together with Great Britain, divided Germany into four occupation zones. Japan alone is therefore not one of the occupying powers.

Japan was an ally, not an occupying power.

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