This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'In an epidemic first to be done is - \nSelect and explain. \nA. Identity the cases, B. Confirm the diagnosis, C. Identify The prone people, D. Identify the causative factors', 'role': 'user'}, {'content': 'Answer: B \nExplanation: verification of diagnosis is the first step in the investigation of an epidemic.it is necessary to examine all cases before arriving at a diagnosis.a clinical examination of a sample of cases may suffice.laboratary investigations can also be employed in such way that it is not delaying any of the epidemiological investigations concerned. ref:park&;s textbook,ed22,pg no 123', 'role': 'assistant'}]