What is Rio+20 Conference, often mentioned in the news?

 a)  It is the United Nations Conference on Sustainable Development
 b) It is a Ministerial Meeting of the World Trade Organization
 c) It is a Conference of the Inter-governmental Panel on Climate Change
 d) It is a Conference of the Member Countries of the Convention on Biological Diversity

IAS Prelim-15

It is the United Nations Conference on Sustainable Development .