Who referred to the domino theory as a reason to support liberation of communist countries? eisenhower truman johnson roosevelt

The correct answer is Eisenhower 

He believed that if a single country fell to a communist regime, they it would create an effect like dominoes that fall and that all others would fall down. That's the reason why the United States intervened in both Korea and Vietnam. Unlike Korea, the US weren't capable of preventing the victory of Communism in Vietnam.

Ithink it’s c , good luck on whatever : )