Answer:
For 1 it is
The Yalta Conference, also known as the Crimea Conference and code-named the Argonaut Conference, held February 4–11, 1945, was the World War II meeting of the heads of government of the United States.
for 2 it is The primary purpose of the “Yalta Conference” was to discuss the re-establishment of the nations of war-torn Europe.
for 3 it is meeting they did a lot of meetings.
for 4 it is optimism for the future of the continent.