Hihi!
The answer is the last one! Détente ended after the Sovietinvaded in Afghanistan, that led to the United States boycott of the 1980 Olympics in Moscow. Ronald Reagan's election as president in 1980, also took part in a large sum on an anti-détente campaign, this made the close of détente and a return to Cold War.
I hope I helped!
-Jailbaitasmr