The correct answer is A) removal of the Berlin Wall.
The "sign" that Reagan referred to in this excerpt was the removal of the Berlin Wall.
During Ronald Reagan's speech at the Brandenburg Gate, West Berlin, 1987, the President of the United States boldly stated "Mr. Gorbachev, tear down the wall." He referred to tear down the Berlin Wall that had separated East and West Germany since 1961. Reagan said that if the USSR wanted to move to liberty and peace, the Soviet Union needed to open the doors between the two Germanies.
