What does the abbreviation SPD stand for?

EDITORIAL LEARNING AID

Why is this answer correct?

For the “Leben in Deutschland” test, connect “Social Democratic Party of Germany” with the meaning of the question. This is the answer marked as correct in the official key. “Socialist Party of Germany” is not part of the solution and points to a different issue. Learn the key term together with the complete correct answer instead of memorising only its letter.

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