Answer: B. SALT, Helsinki Accords, and U.S meeting with the USSR during the 1970's
Explanation: Detente is an expression that indicates the relaxation of already tense relations, usually between the two countries. This term in the 20th century is related to the period of relaxation of relations between the United States and the Soviet Union during the Cold War, and it occurred in the early 1970's. The key event during the detention was the meeting of US President Nixon and the Soviet President Brezhnev. In addition to that meeting, agreements such as SALT I and Helsinki Accord were initiated.
SALT (Strategic Arms Limitation Talks) were two rounds of conferences, on reduction and control of weapons.
Helsinki Accords was a conference on security and cooperation in Europe.
The period of relaxation of the relationship (detente) was completed by the USSR attack on Afghanistan in 1979.