Question

The new Japanese constitution after World War II contained a clause that
promised that Japan would remain allies with the US.
prevented Japan from having or using an army.
required all citizens to vote in Japanese elections.
stopped Japan from making special trade agreements.

Answer 1

Prevented Japan from having or using an army.

Article 9 of the 1947 constitution renounces war and forbids Japan from maintaining armed forces with war potential (the later Self‑Defense Forces arose under reinterpretation of that clause).