Answer:
B. containment
Step-by-step explanation:
1) The wording of this question is extremely poor.
The U.S. never put in a foreign policy to "stop the containment of communism". The U.S. put in a foreign policy of containment, to stop the spread of communism. 2) It is the U.S.S.R that put in the policy of glasnot, or "opening of the door", which allowed them to transition from Communism to Free Market Enterprise. Never did the U.S. make that change.