Answer:
A. Warsaw Pact
The Warsaw Pact was a military alliance formed in Eastern Europe after World War II. It was established in 1955 by the Soviet Union and its satellite states in Eastern Europe, including Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, and Romania. The Warsaw Pact was created as a counterbalance to the military alliance of Western European countries, NATO (North Atlantic Treaty Organization) and it was dissolved in 1991 after the fall of Soviet Union.