What is the full form of START?

Strategic Arms Reduction Treaty

The correct answer is Option (2) → Strategic Arms Reduction Treaty

START stands for Strategic Arms Reduction Treaty. There were two START treaties:

STRATEGIC ARMS REDUCTION TREATY I (START-I): Treaty signed by the USSR President Mikhail Gorbachev and US President George Bush (Senior) on the reduction and limitation of strategic offensive arms in Moscow on 31 July 1991.

STRATEGIC ARMS REDUCTION TREATY II (START-II): Treaty signed by the Russian President Boris Yeltsin and the US President George Bush (Senior) on the reduction and limitation of strategic offensive arms in Moscow on 3 January 1993.