Earth Summit which was held in Rio De Janerio focussed on:

Sustainable Development

The correct answer is Option (3) - Sustainable Development

Earth Summit which was held in Rio De Janerio focussed on Sustainable Development.

The growing focus on environmental issues within the arena of global politics was firmly consolidated at the United Nations Conference on Environment and Development held in Rio de Janeiro, Brazil, in June 1992. This was also called the Earth Summit.
The summit was attended by 170 states, thousands of NGOs and many multinational corporations. The Rio Summit produced conventions dealing with climate change, biodiversity, and forestry, and recommended a list of development practices called ‘Agenda 21’. But it left unresolved considerable differences and difficulties. There was a consensus on combining economic growth with ecological responsibility. This approach to development is commonly known as ‘sustainable development.