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': 'Epidemiological studies is carried for a period of - \nSelect and explain. \nA. Incubation period, B. Twice the incubation period, C. Four times the incubation period, D. Half the incubation period', 'role': 'user'}, {'content': 'Answer: B \nExplanation: .epidemiological studies are usually employed for a period of twice the incubation period .it is done so so thzt most of the cases and associated risk factors are identified in such a way that it may help in the interpretation of data collected and thus the epidemiological analysis. ref:park&;s textbook,ed 22,pg no 67', 'role': 'assistant'}]