This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Health programmes in India, Subject name: Social & Preventive Medicine
[{'content': 'Under RCH programme, intervention done in selected districts- \nSelect and explain. \nA. Immunization, B. Treatment of STD, C. ORS therapy, D. Vitamin A supplementation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: <p> Treatment of STD done in selected districts. Reference:Park&;s textbook of preventive and social medicine,K.Park,23rd edition,page no:453 <\\p>', 'role': 'assistant'}]