The correct answer is A. UNESCO.
The Man and Biosphere Programme (MAB) is an intergovernmental scientific programme coordinated by UNESCO. It aims to establish a scientific basis for the rational use and conservation of the biosphere and to develop models for sustainable development.
The IUCN (International Union for Conservation of Nature) is an independent, global union composed of government and non-governmental organizations that are committed to the conservation of nature.
The WWF (World Wide Fund for Nature) is an international non-governmental organization founded in 1961, working on issues regarding the conservation, research and restoration of the environment.
The WIPO (World Intellectual Property Organization) is an intergovernmental organization that promotes the protection of intellectual property rights.
The MAB Programme is affiliated with UNESCO because it is a scientific programme that aims to promote the conservation and sustainable use of the biosphere. UNESCO is a specialized agency of the United Nations that is responsible for education, science, culture, and communication.