India is a member of the Indian Ocean Rim Association for Regional Cooperation (IOR-ARC). This organization is an intergovernmental organization established in 1997 to promote economic and technical cooperation among the Indian Ocean Rim countries. It focuses on areas such as trade facilitation, investment promotion, fisheries management, disaster risk reduction, and academic and cultural exchanges.

However, India is not a member of the Organisation for Economic Cooperation and Development (OECD). The OECD is a forum where governments work together to address economic, social, and environmental challenges. It consists of 37 member countries, mostly high-income economies. India has not yet been invited to join the organization, although it has been engaged in dialogue and collaboration with the OECD on various issues.

Therefore, the correct answer is option 1: India is only a member of the Indian Ocean Rim Association for Regional Cooperation.