Answer:
The result of the Big Three Allied leaders' meeting at Yalta was that they decided the Soviet Union should enter the war against Japan.
Explanation:
The Yalta Conference was the meeting held before the end of the Second World War (February 4 to 11, 1945) by Joseph Stalin, Winston Churchill and Franklin D. Roosevelt, as heads of government of the Soviet Union, the United Kingdom and of the United States, respectively.
Among several other agreements, the USSR undertook to intervene in the war with Japan three months after the German surrender. In return, it would be given the island of Sakhalin and the Kuril Islands, as well as several privileges.