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.

By the time of the Yalta Conference, the Soviet Union had to declare war on Japan and Joseph Stalin agrees to enter war against Japan because the Soviet Union was to be granted a sphere of influence in Manchuria. The correct option in regards to the given question is option "C". During the Yalta Conference, Joseph Stalin was assured by Roosevelt about supporting Stalin's far eastern territorial desires. Based on this fact, Stalin agreed to enter the war and attack Japan within 2 or 3 months. The Yalta Conference was held in the month of February of the year 1945.