Woodrow Wilson hardened Senate opposition to the Treaty of Versailles by his refusal to compromise on the issue of
A. Reparations limited to the amount of Germany could afford to pay
B. Plebiscites to determine the new borders of Germany
C. The border between Italy and Yugoslavia
D. Protectorate status for African colonies seized form Germany
E. The unconditional adherence of the United States to the charter of the League of Nations

Question

Woodrow Wilson hardened Senate opposition to the Treaty of Versailles by his refusal to compromise on the issue of 
A. Reparations limited to the amount of Germany could afford to pay
B. Plebiscites to determine the new borders of Germany
C. The border between Italy and Yugoslavia
D. Protectorate status for African colonies seized form Germany
E. The unconditional adherence of the United States to the charter of the League of Nations

opcode · Answer

In truth none of those answers are worth the question.
What you teacher probably wants is E. The unconditional adherence of the United States to the charter of the League of Nations.
I've also attached a .pdf if you want to know more about this issue. (Read about his speech.)