B. is the correct answer I took the test.
Berlin--communism was contained by splitting the city of Berlin between East and West instead of allowing the capital city to fall under the control of the USSR
Korea--the US with the United Nations partitioned Korea into North and South with the North under the influence of the USSR and the South under the influence of the West. The advance of the North was prevented and the partition remained following the Korea War.
Cuba--though Cuba became a communist nation, the US attempted overthrows and potentially an assassination of the communist leader Fidel Castro. When the USSR attempted to put missiles in Cuba, the US was able to negotiate and prevent the missiles.
