Correct Answer: October 24, 1945

Solution : The correct option is October 24, 1945.

The United Nations is an intergovernmental body, whose declared goals are to uphold international peace and security, foster goodwill among nations, promote international collaboration, and operate as a hub for harmonizing national policies. 50 countries gathered in San Francisco, California, for a summit on April 25, 1945, and began drafting the UN Charter, which was approved on June 25, 1945. The UN started operating on October 24, 1945, when the charter came into effect.