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: Surgery
Half life of iodine 131 is? 
Select and explain. 
A. 6 days, B. 4 hours, C. 8 days, D. 13.5 hours
C: 8 days
Answer: C: 8 days 
Explanation: lodine 131 is used for radioiodine ablation.