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
Long term fluctuation is 
Select and explain. 
A. Secular, B. Cyclical, C. Seasonal, D. Periodic fluctuation
A: Secular
Answer: A: Secular 
Explanation: Ans. is 'a' i.., Secular