Answer:
The answer is D: The US and Soviet Union returned to competition rather than cooperation to gain power
Step-by-step explanation:
Détente means "an ending of unfriendly or hostile relations between countries,". The breakdown in détente efforts was caused by miscommunications of what the word détente actually meant. The breakdown was also caused by the two countries having unrealistic expectations of what the other country needed to do to end the Cold War. These led to the further competition between the United States and the Soviet Union, when it was originally meant to unify them.