Explanation:

1st option is correct. The Kyoto Protocol is an international treaty which extends the 1992 United Nations Framework Convention on Climate Change (UNFCCC) that commits State Parties to reduce greenhouse gas emissions, based on the scientific consensus that (a) global warming is occurring and (b) it is extremely likely that human-made CO2 emissions have predominantly caused it.
The Montreal Protocol on Substances that Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion.
Vienna Convention is for the Protection of the Ozone Layer.
Agenda 21 is a non-binding, voluntarily implemented action plan of the United Nations with regard to sustainable development.