During which one of the following was the Convention on Biodiversity opened for signature?

The Convention on Biological Diversity was opened for signature at the Rio Earth Summit held in 1992.

This United Nations Conference on Environment and Development took place in Rio de Janeiro, Brazil.

The Stockholm Conference of 1972 launched global environmental diplomacy but predates the biodiversity treaty.

The Ramsar Convention deals specifically with the conservation of wetlands, not overall biodiversity.

The Montreal Protocol targets substances that deplete the ozone layer, a separate concern.

The same Rio Summit also opened the Framework Convention on Climate Change for signature.