What led to the signing of the nuclear test ban treaty?

The correct answer is the Cuban Missile Crisis.

Explanation:

The Partial Nuclear Test Ban Treaty is the name given to the treaty whose main purpose was to prohibited all test detonatios of nuclear weapons in the atmosphere, in outer space and under water, except for those conducted underground, signed in 1963 by many presidents but principle by John F. Kennedy and Nikita J. Khrushchev.

In 1962, the Cuban Missile Crisis took place, comprehending the confrontation between both The United States and The Soviet Union that almost led to a the nuclear war and it gave both leaders the reason to accelerate the process of rapprochement between them. Therefore that after a few years of trying peace between them, Khrushchew suggested the partial ban.