Secretariate of Convention on Biodiversity (CBD) is situated in

The correct option is Montreal, Canada.

Explanation:
The Convention on Biological Diversity (CBD) is a landmark international treaty that was opened for signature at the Earth Summit in Rio de Janeiro in 1992 and entered into force in December 1993. It aims to promote sustainable development through three main objectives: the conservation of biological diversity, the sustainable use of its components, and the fair and equitable sharing of benefits arising from genetic resources.

The Secretariat of the Convention on Biological Diversity (SCBD) is responsible for organizing meetings, drafting documents, assisting member governments, and coordinating with other international organizations to support the implementation of the convention. The Secretariat is hosted by the United Nations Environment Programme (UNEP) and has been located in Montreal, Canada, since it became operational there in 1996.