This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'Polio is said to be eradicated if no case of polio by wild poliovirus occurs in an area for ? \nSelect and explain. \nA. 1 year, B. 2 years, C. 3 years, D. 4 years', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., 3 years Ceification of polio eradication is conducted an regional bases. Each region can consider ceification only when all countries in the area demonstrate the absence of wild poliovirus transmission for at least three consecutive years.", 'role': 'assistant'}]