Read the excerpt from President Reagan’s speech. Are these the beginnings of profound changes in the Soviet state? . . . We welcome change and openness; for we believe that freedom and security go together, that the advance of human liberty can only strengthen the cause of world peace. There is one sign the Soviets can make that would be unmistakable, that would advance dramatically the cause of freedom and peace.

—Ronald Reagan,

Speech at the Brandenburg Gate, West Berlin, 1987

What "sign" was Reagan referring to in this excerpt?

removal of the Berlin Wall

expansion of Gorbachev’s reforms

peaceful democratic revolutions in Eastern Europe

inspections to enforce conditions of the SALT treaties