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 case of acute flaccid paralysis must be observed for how many days for residual weakness 
Select and explain. 
A. 30 days, B. 42 days, C. 60 days, D. 90 days
C: 60 days
Answer: C: 60 days 
Explanation: Ans. is 'c' i.e., 60 days