A.Traties is the answer probably.I had some hard thinking and came up with this.
The name for this idea is "Domino Effect" - this is a theory that says that if one country falls to Communism the neighboring countries would also fall to Communism, much like pieces of Dominos fall when a neighboring piece fell.
This theory was important in the Foreign politics of the US during the cold war.
D, allowing people to keep their local traditions
Answer: D is right. But there are also many other reasons.
Explanation: League of Nations was formed by Allied powers (from the WW I) so consequently it was viewed as "League of Victors". Moreover USA did not join, may other states did not join and later on League of Nations was unable the prevent outbreak of WW II.
Answer:
England that is the answer