The Soviet Union had set up official border stations in which you had to cross to get to the other side. Eventually, they had set it up so they're was only one safe way to get to West Berlin, just one border stations. These border stations were quite strict, as they had people trying all sorts of crazy ways to get to West Berlin.
Isolationism was the policy that kept them from joining the League of Nations. Isolationism is when a group stays away from or ignores all people in that group. Mainly political matters of other countries.
Answer:
la época del boom en Latinoamérica fue lo que dejo que la gente se volviera más moderna y ayuda a crear la Latinoamérica que ahora conocemos.
I believe it would be D)All The Above