I think the right answer is C.(William Penn)
Answer: The answer is complex and not straightforward.
Explanation:
The article relates to Churchill and Roosevelt, so is probably dated from World War 2.
Given this and the reference to the use of force by aggressive nations it is reasonable to assume that this refers to the Axis nations and their allies, primarily Germany, Japan and Italy.
What is being referred to is reflected in the policies applied to Germany and Japan at the end of World War 2. (Italy had already switched sides and deposed Mussolini).
In the post war agreements drawn up, Germany and Japan were largely demilitarised with strict control over their armed forces. In the case of West Germany their limited armed forces existed only within the context of NATO to prevent any aggressive use as was evidenced at the beginning of World War 2.
In both instances these countries were not allowed to develop or possess nuclear weapons.
Until such time as there is a global disarmament treaty, as referred to in the article, then countries which are deemed "aggressive", the losers in a conflict, by others, the winners, have arms controls imposed.
Of course this does not and has not stopped the proliferation of weapons, and conflicts throughout the world since 1945, including the aggressive policies of countries such as the UK and the USA.
B. Pressure from Nelson Mandela and the United Nations led to it's fall.
A) The South didn't need to conquer the North to win its independence.
The South was just planning on defending itself till the North grew tired, but the North had to conquer the South to be able to reunite the Union and win the war.
