Final answer:
The U.S. Senate rejected the Treaty of Versailles due to concerns about the League of Nations' potential to entangle the U.S. in international conflicts and undermine congressional power to declare war. The option (C) is correct.
Step-by-step explanation:
The U.S. Senate rejected the Treaty of Versailles primarily due to concerns over the League of Nations. Senators feared that Article X of the League of Nations' covenant would compromise U.S. sovereignty by allowing American troops to be sent into foreign conflicts without the explicit approval of Congress, which holds the constitutional power to declare war.
Objections were also raised regarding the dominance of Britain and France in controlling the League, which influenced the Senate's decision to reject the treaty and led to the U.S. not joining the League of Nations. Therefore, option (C) is correct