In what way did the reunification of Germany lead to the downfall of the Soviet Union? O A. It caused United States troops to enter countries in Eastern Europe.
О
B. It allowed the United States to encourage education in Eastern Europe.
OC. It inspired countries in Eastern Europe engage in war to overthrow Soviet rule.
O D. It forced Soviet leaders to withdraw troops from Eastern Europe.

Correct answer is  D. It forced Soviet leaders to withdraw troops from Eastern Europe.

Explanation:

A is not correct as American troops haven't entered that territory at all.

B is not correct as United States were not able to affect all this changes that much.

C is not correct as there were not wars in Europe, except the one Yugoslavia, which was not even under the influence of Soviet Union.

D is correct because Soviet troops withdrew, and new democratic regimes were established in those countries.

there is an explationation of this on a site called crash   course world history 1

if im not mistaken its a. collective emotional arousal