This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2018, Subject name: Radiology
Iodine isotope used for radio ablation of thyroid in Graves' disease is: 
Select and explain. 
A. I-125, B. I-123, C. I-131, D. I-124
C: I-131
Answer: C: I-131 
Explanation: Radio-isotopes Half-life Uses I-131 8 days Radio ablation of thyroid gland Systemic radiotherapy of thyroid metastasis I-125 60 days Brachytherapy (prostate cancer) Radio-immunoassay I-124 4 days Positron emitter (PET) I-123 13 hours Functional scanning of thyroid gland Thyroid scintigraphy Radio-active Iodine Uptake (RAIU)