The International Solar Alliance (ISA) is an international treaty-based organization launched to promote solar energy globally. It was jointly launched by India and France on 30th November 2015, during the COP-21 summit held in Paris, France.
The ISA aims to bring together sun-rich countries to collectively work on solar energy projects and reduce dependence on fossil fuels. It primarily focuses on countries located between the Tropics of Cancer and Capricorn.
Therefore, the correct answer is (1) COP-21.