The correct response is: The domino theory describes the U.S. policy for stopping the Soviet Union from influencing other countries in which people were staging revolutions and independence movements.
The domino theory suggested that the spread of communism in one country could lead to the spread of communism in neighboring countries, much like a falling domino. This theory played a significant role in U.S. foreign policy during the Cold War, driving efforts to prevent the influence of the Soviet Union and support anti-communist movements worldwide, particularly in regions experiencing revolutions or independence movements.