How Did Nuclear Weapons Help Lead to the "Long Peace

How did nuclear weapons help lead to the "Long Peace"?

A) Other nations worked to keep both sides in check to prevent the use of nuclear weapons.
B) Peace was maintained through international monitoring of nuclear weapon stocks.
C) Both powers spent so much money on developing new nuclear technologies that they could not afford war.
D) Because both powers had second-strike capability,neither was willing to start a direct war.
E) Only when one side agreed to share its nuclear secrets with the other could peace occur.