"According to Traditionalist Historian, Thomas A. Bailey, the breakdown of postwar peace was the result of Soviet expansionism in the immediate postwar years. Bailey argued Stalin violated promises he had made at Yalta, imposed Soviet-dominated regimes on unwilling Eastern European populations, and conspired to spread communism throughout the world. From this view, U. S. officials were forced to respond to Soviet aggression with the Truman Doctrine, plans to contain communist subversion around the world, and the Marshall Plan." Based on the quote above, what is the agreement made at Yalta (which Stalin violated) that Bailey is most-likely referring to?

Group of answer choices

Hallstein Doctrine

Baruch Plan

Declaration of Liberated Europe

UN Resolution 83