Why was the United Nations formed?

to promote Communism

to engage in armed conflict

to defend nations against attack

to promote international peace

United Nations is formed by the Treaty of San Francisco in 1945, as a replacement of the ineffective League of Nations. The purpose of the formation of the United Nations is to prevent a global scale war happening again and promote international peace among the globe, to show that they'll send in peacekeeping forces in disputed regions and civil wars.

B. To defend nations against attack.