President Dwight Eisenhower sent aid to Vietnam because of the Domino Theory. What does this theory state?

A) It states that if you defend other countries around the world, you gain allies.

B) It states that if one country becomes communist, so will many others.

C) It states that the U. S. needs to show its power to others to prove that it is superior.

D) It states that the U. S. needs to assist poor countries of the world.