Answer:
a. Promotes international peace, security, and cooperation under the terms of a charter signed by 51 founding countries.
Explanation:
In order to achieve this, United Nations created several specialized groups Each groups are task to handle a specific issue to achieve United Nations' goals.
For example, to promote international peace and security, United Nations established the UN Security Councils with five permanent members (United States, Russia, China, France, and United Kingdom). The council was heavily involved in operations to maintain peacekeeping around the world, enacting international sanctions for violator of human rights, and authorizing military action when deemed necessary.
The United States have many more specialized agencies to tackle different varieties of issues such as handling conflict among countries on an international trade, providing food & education for children in poverty, etc.
