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
Secular trend is a - 
Select and explain. 
A. Long term, B. Sho term, C. Both, D. None
A: Long term
Answer: A: Long term 
Explanation: Ans. is 'a' i.e., Long term