Answer:
The policy of containment changed after the collapse of the Soviet Union because it was no longer relevant now that the Soviet Union was gone and was not trying to spread communism. Therefore, the correct answer is "It was no longer relevant now that the Soviet Union was gone and was not trying to spread communism."
Containment was a Cold War policy of the United States to prevent the spread of communism beyond its existing borders. With the collapse of the Soviet Union, the communist threat that had spurred the policy of containment no longer existed. As a result, the policy of containment became obsolete and was no longer a relevant approach to foreign policy. While Britain and France had also adopted policies of containment during the Cold War, their policies also became irrelevant with the collapse of the Soviet Union.