The correct option is "1 only" because the Green Climate Fund (GCF) is specifically established under the United Nations Framework Convention on Climate Change (UNFCCC) to support developing countries in their efforts towards climate change mitigation and adaptation. While it collaborates with various organizations and funding entities, it is not founded under the aegis of UNEP, OECD, Asian Development Bank, and World Bank, but rather operates independently under the UNFCCC. This distinction is important in the context of global climate finance mechanisms and emphasizes the GCF's role in the international climate agreement framework.