The right answer is the letter D.
Here is a brief explanation of this:
The World Health Organization (WHO) is responsible for leading issues and partnerships for health development, for stimulating scientific research, for setting standards in the area, for providing technical support and for monitoring the health situation in the world. In addition, it sponsors programs to prevent and treat malaria and tuberculosis, supervises the implementation of the International Health Regulations, conducts health campaigns, promotes research on diseases of various categories in several countries and publishes periodicals for the development of the area.