The correct option is D Switzerland
The World Health Organisation or the WHO is a special organ of the United Nations, established in 1948, and headquartered in Geneva, Switzerland. It aims to further international cooperation for improved public health conditions. The WHO keeps member countries informed of the latest developments in cancer research, drug development, disease prevention, control of drug addiction, vaccine use, etc. It also sponsors measures for the control of epidemic diseases by promoting mass campaigns. It has had some success against AIDS, tubercolosis, malaria, and a variety of other diseases.