I would say id depends if you care about people any color, or size.
I believe the answer is C.
The entry of the US into WWI really boosted the Allied Powers' morale, while destroying the morale of the Central Powers.
While the rest of the Allies had been fighting for nearly four years at this point, when the US entered, they were fresh, energized, and idealistic.
Basically, US soldiers encouraged the other Allies and helped them get their mojo back.
The Iron Curtain, because the Domino theory was based on the fact that the democratic countries wanted to prevent the spread of Communism
