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': 'True about polio vaccination is all EXCEPT - \nSelect and explain. \nA. Follow up of AFP for 30 dyas, B. Salk contains three types of polio virus, C. Pulse polio doses are extra and supplemental, D. Oral polio vaccine provides intestinal immunity also', 'role': 'user'}, {'content': 'Answer: A \nExplanation: <p> Follow up in 60 days. Reference:Park&;s textbook of preventive and social medicine,K.Park,23rd edition,page no:203. <\\p>', 'role': 'assistant'}]