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': 'Epidemic is - \nSelect and explain. \nA. Short term fluctuation, B. Log term fluctuation, C. Secular trend, D. All of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Short term fluctuation * There are three kinds of time trends or fluctuations in disease occurenceA. Short term fluctuations - epidemics.B. Secular trends or long term fluctuations.C. Periodic fluctuation.", 'role': 'assistant'}]