You didn't provide choices, but the main reason for refusing entry into the League of Nations was the belief that doing so meant giving up some of the United States' own sovereignty and could commit the US to defend other nations' security rather than its own.
Context/detail:
The United States never joined the League of Nations, in spite of the fact that an organization such as the League of Nations was the signature idea of US President Woodrow Wilson. He had laid out 14 Points for establishing and maintaining world peace following the Great War (World War I). Point #14 was the establishment of an international peacekeeping association. The Treaty of Versailles adopted that idea, but back home in the United States, there was not support for involving America in any association that could diminish US sovereignty over its own affairs or involve the US again in wars beyond those pertinent to the United States' own national security. Because of its objections to membership in the League of Nations, the United States Senate refused to ratify the Treaty of Versailles.
<span>Rather than allow senators to
accompany him to Paris for treaty negotiations following World War I,
President Wilson insisted upon having exclusive control over the terms
of the treaty. Congress was dissatisfied, however, particularly with an
article that would require members of the League to defend one another
in the event that one was attacked. Lodge and Wilson had been engaged in
a power struggle brought about as the result of each thinking himself
intellectually and professionally superior to the other. Since Senator
Lodge was both the Senate Majority Leader and the Chairman of the
Foreign Relations Committee, Wilson needed his support in order for the
treaty to be passed. Instead of seeking support, however, Wilson spoke
negatively of Lodge. This angered supporters of Lodge. As a result, by
the time the treaty reached the floor of the Senate for a vote, 14
reservations had been attached to it. The rejection of the Treaty of
Versailles and the League of Nations was the first time the U.S.
Congress rejected a treaty.</span>
It was mostly spent on purchasing more land. This meant that they could then open new factories for industrialization and manufacturing, which meant they could get more money and trade more slaves, and then buy more land, and so it went until slavery was banned.
