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': "All are true about surveillance except \nSelect and explain. \nA. It is continuous scrutiny of factors, B. Feedback present, C. Helps in national health program's, D. Stops once disease is eliminated / cradicated", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]