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
Cyclical trend of occurrence of disease is shown by all except 
Select and explain. 
A. Measles, B. Rubella, C. Influenza, D. Polio
D: Polio
Answer: D: Polio 
Explanation: Cyclical trend is occurance of disease in cyclical pattern
Eg :

Measles : every 2-3 years.
Rubella : every 6-9 years.
Influenza : every 10-15 years (pandemic).

Polio cases occurance is considered as epidemic / short term fluctuation.