Misc: What's the infamous contraction of Geheime Staatspolizei?

Questions

lb What was the nationality of the abstract artist, Mondrian?

Which group had their first U.K. number one tilt ill 1974 with Down Down?

Which group had their first U.K. number one hit ill 1973 with RubberBullets?

What replaced English as the official language of Kenya in 1974?

What is the capital of the Canadian province of British Columbia?