It marked the first attempt to restrict U.S. and Soviet nuclear weapons, is the right answer.
The full form of SALT I is the "Strategic Arms Limitation Talks Agreement". There were two rounds of bilateral conventions and identical international treaties including the U.S. and the USSR. Among the two the first one is known as SALT I. It was approved on 26th May 1972. These were meant to restrict the arms competition in strategic (long-range) ballistic projectiles loaded with nuclear weaponry.
