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
Most common cause of Thyroiditis is - 
Select and explain. 
A. Reidl' s Thyroiditis, B. Subacute Thyroiditis, C. Hashimoto's Thyroiditis, D. Viral thyroiditis
C: Hashimoto's Thyroiditis
Answer: C: Hashimoto's Thyroiditis 
Explanation: None