This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
[{'content': 'Sentinel surveillance of HIV is done all except - \nSelect and explain. \nA. Disease trend, B. High risk group, C. Monitor effectiveness of control program, D. Population at risk', 'role': 'user'}, {'content': 'Answer: C \nExplanation: <p> HIV sentinel surveillance is used to calculate -high risk population. -prevalence of HIV. -trend finding among population. Reference:Park&;s textbook of preventive and social medicine,K.Park,22nd edition,page no:318,322. <\\p>', 'role': 'assistant'}]