This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Physics of Radiotherapy, Subject name: Radiology
Half life of I 131 is: (Repeat) 
Select and explain. 
A. 13 days, B. 8 days, C. 2 days, D. 12 hours
B: 8 days
Answer: B: 8 days 
Explanation: Ans: B (8 days) Ref: Internet SourceExplanation:Refer JIPMER 2012 Radiology.