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
Shoest incubation period is of which infection ? 
Select and explain. 
A. Chicken pox, B. Measles, C. Rubella, D. Influenza
D: Influenza
Answer: D: Influenza 
Explanation: Ans. is 'd' i.e., Influenza