What was an effect of the Berlin Crisis?

AIt started the building of the Berlin Wall.
BIt started the depopulation of East Germany.
CIt brought an end to the Cold War.

Verified Answer :

Perhaps the greatest effect of the Berlin Crisis was that "A. It started the building of the Berlin Wall," since an agreement could not be reached regarding the west un-occupying west Germany. 

It started the building of the Berlin Wall is the answer