Gorbachev's Reform Policy

During the late 1980s, a series of events unfolded that led to the end of the Cold War. One of the significant factors in this process was the policy shift in the Soviet Union under Mikhail Gorbachev, who introduced reforms that aimed to reduce tensions with the West. Which of the following policies was implemented by Gorbachev and played a crucial role in the rapprochement between the United States and the Soviet Union?