This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'Iodine deficiency control programme ? \nSelect and explain. \nA. Health education, B. Water testing, C. Foification of salt, D. None', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Foification of salt Iodized salt (salt foified with iodine) is most economical, convenient and effective means of mass prophylaxis in endemic area.", 'role': 'assistant'}]