The United Nations officially came into existence on October 24, 1945, after the Charter had been ratified by China, France, the Soviet Union, the United Kingdom, the United States, and a majority of other signatories. This day is now celebrated annually as United Nations Day.

At the conclusion of the United Nations Conference on International Organization in San Francisco, 50 nations signed the Charter on June 26, 1945. Poland, which was not present at the conference, signed later and became the 51st original member.

The Yalta Conference took place in the Crimea (Yalta) from February 4 to 11, 1945. The leaders (Roosevelt, Churchill, Stalin) discussed the post-war reorganization of Germany and Europe. Crucially, they agreed on the voting formula for the UN Security Council, paving the way for the San Francisco conference.

The Dumbarton Oaks Conference was actually held from August to October 1944. However, in the context of the given options, the proposals are often associated with the late 1944 period leading into 1945. The proposals formulated here formed the basis for the UN Charter. Note: The options provided in the question (A: Dec 1944) are the closest fit for the conclusion of these talks in late 1944.

The Tehran Conference (codenamed Eureka) was held in Tehran, Iran. It was the first strategy meeting of the 'Big Three' leaders (Roosevelt, Churchill, and Stalin). The conference ran from November 28 to December 1, 1943, focusing on the next phases of the war and the opening of a second front in Europe.

This refers to the Moscow Conference of Foreign Ministers. On October 30, 1943, the 'Moscow Declaration on General Security' was signed. It explicitly recognized the necessity of establishing a general international organization at the earliest practicable date for the maintenance of international peace and security.

The 'Declaration by United Nations' was signed on January 1, 1942, during the Arcadia Conference. Representatives of 26 governments, including the 'Big Four' (US, UK, USSR, China), pledged to fight against the Axis powers and not to make a separate peace. This was the first official use of the term 'United Nations'.

The Atlantic Charter was a pivotal policy statement issued during World War II. It was drafted by Franklin D. Roosevelt and Winston Churchill at the Atlantic Conference and issued on August 14, 1941. It defined the Allied goals for the post-war world, including the restoration of self-government and global cooperation, laying the groundwork for the UN.

An **MA** is a master's degree awarded by universities or colleges upon completion of a course of study demonstrating mastery or a high-order overview of a specific field of study or area of professional practice.

The **FDA** is responsible for protecting the public health by ensuring the safety, efficacy, and security of human and veterinary drugs, biological products, and medical devices; and by ensuring the safety of our nation's food supply.