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
A country is certified for Polio eradication, if there is no virologically confirmed diagnosed case of polio for the last years - 
Select and explain. 
A. 1, B. 2, C. 3, D. 5
D: 5
Answer: D: 5 
Explanation: None