Answer & Explanation
Option: It was signed in 1992 between NATO members and former Warsaw Pact countries following the demise of the Soviet Union.
Explanation:
Russia was pulling out of the Open Skies treaty, saying that the pact, which allows unarmed surveillance flights over member countries, had been seriously compromised by the withdrawal of the United States. First proposed in 1955 by former US President Dwight Eisenhower as a means to deescalate tensions during the Cold War, the landmark treaty was eventually signed in 1992 between NATO members and former Warsaw Pact countries following the demise of the Soviet Union.