By the time of the Yalta Conference, the Soviet Union had yet to declare war on Japan. What influenced Joseph Stalin to agree to enter the war against Japan?
A. Japan attacked a naval base outside of St. Petersburg.
B. The Soviet Union felt Japan would be an easy enemy to beat.
C. The Soviet Union was to be granted a sphere of influence in Manchuria.
D. Great Britain and the United States agreed to give the territory of Poland to the Soviet Union.