This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
Shoest incubation period is seen with 
Select and explain. 
A. Influenza, B. Hepatitis B, C. Hepatitis A, D. Rubella
A: Influenza
Answer: A: Influenza 
Explanation: Influenza has an incubation period of 18 to 72 hours Incubation period of :- Hepatitis A : 10 to 50 days Hepatitis B : 30 to 180 days Rubella : 2 to 3 weeks Ref : Park&;s Textbook of Preventive and Social Medicine; 23rd edition