Answer:
Allowing free elections in Eastern Europe.
Step-by-step explanation:
The Yalta Conference was a WWII conference of the chief of the allied - President Roosevelt, Winston Churchill, and Joseph Stalin -. During this conference, the future of Poland and Eastern Europe was discussed, also the occupation of Germany.
At the time, the conference was considered successful, but it was marked by the betrail of Stalin after he broke promises not allowing free elections in Eastern Europe and installed governments dominated by the Soviet Union.