The best answer is B.
The Warsaw pact is the name commonly given to the treaty between Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, Romania and the Soviet Union which was signed in Poland in 1955 and was officially called The Treaty of friendship, Co-operation and Mutual Assistance. It was called the Warsaw pact because it was signed in Warsaw.
It was a response to the formation (by western allies) of the North Atlantic Treaty Organization (NATO). West Germany was allowed to join NATO and was allowed to re- militarize and thus the Soviets saw this as a potential threat.
