Correct answer: A. Because it may also include mediation dialogue humanitarian help and development cooperation
Explanation: The United Nations can support peace through many methods, because conflicts are not solved only by military force. It may help opposing sides communicate, mediate negotiations, monitor agreements, support peacekeeping missions, provide humanitarian assistance, and contribute to reconstruction and development. These activities can reduce suffering, build trust, and address conditions that allow conflict to continue. Troops may sometimes be part of a peacekeeping operation, but they are only one instrument and require a political framework.
Option A is correct because it includes mediation, dialogue, humanitarian help, and development cooperation. The other options are clearly incorrect: the UN is devoted in part to international peace and cooperation, it does not exist only to organise sports, and it has many member states. The key idea is that UN peace work is broad and combines diplomatic, humanitarian, security, and developmental efforts.