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
Which type of same can be used to isolate polio virus earliest 
Select and explain. 
A. Stool, B. Blood, C. Throat, D. CSF
A: Stool
Answer: A: Stool 
Explanation: Stool examination Isolation of wild polio virus from stool is 'the recommended method for laboratory confirmation of paralytic poliomyelitis' Recommended in every case of AFP Virus usually can be found in the feces from onset to up to <8 weeks after paralysis, with the highest probability of detection during the first 2 weeks after paralysis onset Ref : Park 25th edition Pgno : 223