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': 'The incubation period of yellow fever is - \nSelect and explain. \nA. 3 to 5 days, B. 3-4 weeks, C. 1 to 2 weeks, D. 8-10 weeks', 'role': 'user'}, {'content': 'Answer: A \nExplanation: <p> YELLOW FEVER:- Zoonoses disease caused by arbovirus. Affects principally monkeys and other veebrates and is transmitted to humans by culicine mosquitoes. Reservoir- mokeys and forest mosquitoes., in urban areas reservoir is man besides Aedes aegypti. A temperature of 24 deg celcius or more required for its multiplication. Incubation period:3-6 days Period of communicability- Blood of patients infective upto first 3-4 days {Reference: park&;s textbook of preventive and social medicine, 23rd edition, pg no.282}</p>', 'role': 'assistant'}]