Why Was the Intermediate-Range Nuclear Forces Treaty (1987) Significant

Why was the Intermediate-Range Nuclear Forces Treaty (1987) significant?

A) It was the first time that United States and Soviet leaders agreed to destroy a whole class of weapons systems.
B) It recognized that the cold war was becoming direr and that Western countries would need to come together to produce more weapons.
C) It was considered the biggest diplomatic failure of Ronald Reagan's presidency and prevented his reelection.
D) It was a formal acknowledgment of an agreement that had already been followed by the Soviets and United States for decades.
E) It was created largely in response to the Soviet Union's booming economy and triumphs in a war against Afghanistan.