Answer:
A. The Cold War ended.
Step-by-step explanation:
There are two significant dates related to the end of the Cold War: the fall of the Berlin Wall on November 9, 1989, and the resignation of Soviet Secretary-General Mikhail Gorbachev on December 25, 1991. The USSR ceased to exist on December 31, 1991. That was the end of communism in Europe and that of the Cold War.