This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infectious Disease Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'All of the following are true for yellow fever EXCEPT \nSelect and explain. \nA. Caused by vector aedes, B. Incubation period of 3-6 days, C. One attack gives life long immunity, D. Validity of vaccination certification begins immediately after vaccination', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. (d) Validity of vaccination certification begins immediately after vaccinationRef : K. Park 23rd ed. /121, 283', 'role': 'assistant'}]