Although Ronald Reagan Had Been a Vigorous Cold Warrior Throughout

Although Ronald Reagan had been a vigorous Cold Warrior throughout his political career, why was he able to bring about a remarkable easing of Cold War tensions?

A) He developed a personal rapport with Leonid Brezhnev.
B) He offered SDI to the Soviet Union.
C) He allowed Casper Weinberger to lead negotiations.
D) He channeled money through the CIA to more moderate members of the Soviet Politburo.
E) He was willing to negotiate with Soviet leader Mikhail Gorbachev.