Why Did Power Transition Realists View Allies and International Institutions

Why did power transition realists view allies and international institutions as less useful in the global war on terror?

A) NATO and other allies did not believe in the same American ideology of spreading democracy.
B) NATO after the Cold War was largely an American enterprise, and the allies had few military assets to fight conflicts outside Europe.
C) The allies had different domestic political frames and, thus, could not reach a consensus on action in Afghanistan and Iraq.
D) The United States had sufficient military power and did not need any assistance following the 9/11 attacks.