Explanation:

Only statements 1&3 are correct.

• The International Solar Alliance (ISA) is focused on promoting solar energy among its member countries, many of which are developing countries with high energy demands. The ISA aims to mobilize efforts against climate change through the deployment of solar energy solutions, particularly in countries that are rich in solar resources but face significant energy demands and challenges in energy access. The Solar Technology Application Resource Centre (STAR C) Initiative is a key initiative by the ISA, aimed at enhancing quality infrastructure (QI) for the uptake of solar energy product and service markets, particularly in least developed countries (LDCs) and small island developing states (SIDS). Recently, Spain has become the 99th member of the International Solar Alliance. 

• Statement 2 is incorrect: 'Towards 1000' strategy of the ISA is aimed at mobilizing USD 1,000 billion of investments in solar energy solutions by 2030, delivering energy access to 1,000 million people using clean energy solutions, and resulting in the installation of 1,000 GW of solar energy capacity. 

Hence option 2nd is correct.