Amajor result of the end of the cold war was
a) the end of apartheid.
b) the fall of the berlin wall.
c) a reduction in nuclear weapons.
d) gorbachev becoming russia's president.

The end of the Cold War. When Mikhail Gorbachev assumed the reins of power in the Soviet Union.
So the answer is D

A major result of the end of the Cold War was?

C. A reduction in nuclear weapons

A major result of the end of the Cold War was a reduction in nuclear weapons. The United States and the Soviet Union signed treaties to decommission many nuclear warheads as the Cold War ended. And remember: the fall of the Berlin Wall happened before the Cold War came to an end, and actually was a symptom of the declining power of the Soviet Union and communist rule.
 
I'm 100% Sure :)