Answer : 2. "Spain"
Explanation :

Spain has joined the International Solar Alliance (ISA) as the 99th member. Ambassador Jose Maria Ridao Dominguez in New Delhi handed over the ratification to Joint Secretary Abhishek Singh. Co-founded by India and France during COP21 in 2015, ISA aims to promote solar energy deployment in member countries to combat climate change, enhance energy access, security and transition.