Answer:
C. He refused to compromise on his idea for the League of Nations.
Step-by-step explanation:
The treaty referred to here is The Treaty of Versailles, the peace treaty between the Allied Powers and Germany, ending World War II. It was overseen by Prime Minister of France Georges Clemenceau, Prime Minister of Italy Vittorio Emanuele Orlando, Prime Minister of the United Kingdom David Lloyd George, and President of the United States Woodrow Wilson. Some things that were arranged in the treaty are, but not limited to: Germany’s territory and sovereignties, and the establishment of League of Nations (today’s United Nations).
League of Nations were not well-received by Congress because at the time, the Republicans were the dominant force in Congress, and they were isolationists; preferring to stay away from international affairs and focusing on keeping United States' affairs close to home. The leader of the Senate, Henry Cabot Lodge, asked for amendments to be done to the Treaty because he feels that the Treaty would cause the US to fall under a greater supranational power as represented by the League of Nations. President Wilson disapproved of these changes, and thus the treaty was never ratified.