The correct answer is: B. Rio de Jeneiro in 1992.
The United Nations Conference on Environment and Development (UNCED), also known as the Earth Summit, was a major United Nations conference held in Rio de Janeiro from 3 to 14 June 1992. The summit was attended by more than 178 governments and 1,400 non-governmental organizations (NGOs). The main outcome of the summit was the Rio Declaration on Environment and Development, which set out 27 principles for sustainable development. The summit also produced Agenda 21, a comprehensive plan of action for sustainable development in the 21st century.
The Earth Summit was the first major international conference to focus on the environment and development. It was a landmark event that helped to raise awareness of the importance of sustainable development. The summit also produced a number of important documents that have shaped international environmental policy in the years since.
The other options are incorrect because:
- Option A is incorrect because the Stockholm Conference on the Human Environment was held in Stockholm in 1972.
- Option C is incorrect because the United Nations Framework Convention on Climate Change was signed in Paris in 1992.
- Option D is incorrect because the United Nations Conference on the Human Environment was held in Stockholm in 1972.