This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'Long term fluctuation is \nSelect and explain. \nA. Secular, B. Cyclical, C. Seasonal, D. Periodic fluctuation', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.., Secular", 'role': 'assistant'}]