When Eisenhower Used the Phrase the "Domino Theory," What Did

When Eisenhower used the phrase the "domino theory," what did he mean?

A) He wanted America diplomats to understand the importance in playing dominos with their counterparts in the Soviet Union.
B) He was referring to his fear that if one country fell to communism that country's neighbors would ultimately also fall to communism.
C) He was comparing the fall of European countries to Hitler because of appeasement.
D) He meant that United States had to correct its own problems or they would create more.
E) He was arguing that the United States had to be the dominant domino in the world.