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
[{'content': 'Shoest incubation period is seen in \nSelect and explain. \nA. Hepatitis A, B. Hepatitis B, C. Rubella, D. Influenza', 'role': 'user'}, {'content': "Answer: D \nExplanation: Influenza Causative Agent: Ohomyxovirus, 3 types : A, B, C Type A: MC cause of outbreaks/Epidemics ; Only cause of Pandemics Type B. Type C: Not circulating currently Incubation period : 18-72 hours Period of Infectivity : 1-2 days before to 1-2 days after onset of symptoms Ref:Park's Textbook of Preventive and Social Medicine 25th Edition Pgno : 167-172", 'role': 'assistant'}]