This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concept of health and disease, Subject name: Social & Preventive Medicine
[{'content': 'True morbidity in a population can be calculated by \nSelect and explain. \nA. Sentinel Surveillance, B. Passive Surveillance, C. Active Surveillance, D. Monitoring', 'role': 'user'}, {'content': "Answer: C \nExplanation: Active Surveillance Extra measures are taken to collect data and confirm diagnoses to ensure more complete repos for surveys and outbreak investigations. Active surveillance encompasses formal and informal communications. Eg: Malaria surveillance by a health worker Main objectives of Surveillance 1. Provide information about new and changing trends in the health status of population - morbidity, moality, nutritional status 2. Provide feedback 3. Provide timely warning Ref: Park's Textbook of Preventive and Social Medicine; 24th edition - Page no. 45", 'role': 'assistant'}]