Concept:The WHO is the United Nations agency dedicated to international public health.Explanation:Nigeria participates actively in the World Health Organization (WHO).WHO coordinates global responses to health emergencies and diseases.It sets health standards and provides technical support to member countries like Nigeria.The other options address different fields: ILO deals with labour, UNESCO with education and culture, and FAO with food and agriculture.Therefore, WHO is the correct UN agency for global health issues.Answer:B. WHO