The correct option is B Finding effective immunisation methods.
WHO helps to fight diseases and prevent them. It also tries to find effective immunisation methods to eradicate communicable diseases. It promotes research for other diseases, like cancer, blindness, diabetes, and heart attack.
Futher, WHO worked with UNICEF in a programme that immunised over 80 per cent of the children in the world against killer diseases, such as measles, diphtheria, tetanus, whooping cough, polio, and tuberculosis.