1) After 2nd world war, charter of newly formed UN established 11 member security council
2) security council charged with taking collective actio in response to threats to world peace
3) charter further provides 5 major powers permanant sole authority to cast vetos
4) reason for this arrangement was that burden of maintainig world peace would rest on world's major powers
5) major powers should therefore be required to assume the burden of enforcing a decision it found repungant

The reasoning given for the structure of the Security Council assumes that

(A) it does not make sense to provide for democracy among nations when nations themselves are not all democracies
-out of scope

(B) no nation that was not among the major powers at the end of the Second World War would become a major power
- I'll go with this choice. The charter reasons that the burden of maintaining world peace should rest on the world's major powers. The arragement for the 5 major powers to have sole authority to cast veto suggests that the UN does not think any other nations will become major powers and none of the major powers will decline drastically in miliatry power.

(C) nations would not eventually gravitate into large geographical blocs, each containing minor powers as well as at least one major power
- not important

(D) minor powers would not ally themselves with major powers to gain the protection of the veto exercised by major powers
- does not matter

(E) decisions reached by a majority of nations in response to threats to world peace would be biased in favor of one or more major powers
- not important

I'll go with (B)

I feel like (B)

(A) it does not make sense to provide for democracy among nations when nations themselves are not all democracies
We are not arguing whether something makes sense.

(B) no nation that was not among the major powers at the end of the Second World War would become a major power
Negation: Some nation that was not among the major powers at the end of the Second World War would become a major power.
This will break the argument below.
The charter further provided that the five nations that were then the major powers would permanently have sole authority to cast vetoes. The reason given for this arrangement was that the burden of maintaining world peace would rest on the world’s major powers and should be required to assume the burden of enforcing a decision it found repugnant.


(C) nations would not eventually gravitate into large geographical blocs, each containing minor powers as well as at least one major power
Irrelevant. If it happens, there is still some major power nations.

(D) minor powers would not ally themselves with major powers to gain the protection of the veto exercised by major powers
Irrelevant. Major power nations are still making decisions and taking burdens.

(E) decisions reached by a majority of nations in response to threats to world peace would be biased in favor of one or more major powers
Have nothing to do with being biased.

I think the "permanant sole authority" is very important.