Question

preventing the outbreak of a new war is the purpose of the
un secretariat.
un security council.
un peacekeeping forces.
international court of justice.

Explanation:

The UN Security Council's main responsibility is to maintain international peace and security, which includes preventing the outbreak of new wars. The UN Secretariat handles administrative tasks. UN peacekeeping forces are deployed after conflicts start (though they can have a role in preventing escalation in some cases but their main role is in post - conflict or during - conflict peacekeeping). The International Court of Justice deals with legal disputes between states.

Answer:

UN Security Council.