Correct Option
The correct option is Adoption of Agenda 21.
Explanation
The United Nations Conference on Environment and Development (UNCED), widely known as the Rio Earth Summit, was held in Rio de Janeiro, Brazil, in June 1992. It was a landmark global conference that aimed to reconcile worldwide economic development with the protection of the environment.
Option Analysis
- Adoption of Agenda 21: Correct. Agenda 21 was a primary outcome of the Rio Earth Summit. It is a comprehensive, non-binding action plan for sustainable development to be executed at global, national, and local levels by UN organizations, governments, and major groups.
- Establishment of the UNEP headquarters in Nairobi: Incorrect. The United Nations Environment Programme (UNEP) was established following the Stockholm Conference on the Human Environment in 1972, not the 1992 Rio Summit.
- Finalisation of the Paris Agreement: Incorrect. The Paris Agreement is a legally binding international treaty on climate change that was adopted much later, at COP 21 in Paris in 2015.
- Signing of the Montreal Protocol: Incorrect. The Montreal Protocol on Substances that Deplete the Ozone Layer was agreed upon in 1987 and entered into force in 1989, predating the Rio Summit.
Key Takeaway
The Rio Earth Summit (1992) resulted in three major non-binding documents: Agenda 21, the Rio Declaration, and the Forest Principles. It also opened two legally binding conventions for signature: the UNFCCC and the Convention on Biological Diversity (CBD).