The United Nations (UN) is an international organization founded in 1945. It has six main organs as its principal components:
- General Assembly
- Security Council
- International Court of Justice
- Secretariat
- Economic and Social Council
- Trusteeship Council
Among the options given:
- Trusteeship Council: This is a main organ of the UN, although its operations are currently suspended.
- Economic and Social Council: This is one of the main organs focusing on economic, social, and environmental issues.
- United Nations Secretariat: This organ is responsible for carrying out the day-to-day work of the UN, led by the Secretary-General.
- United Nations Educational, Scientific and Cultural Organization (UNESCO): This agency is specialized and not considered one of the main organs of the UN.
Therefore, the option that is not a main organ of the United Nations is:
United Nations Educational, Scientific and Cultural Organization (UNESCO)