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
Thyroid carcinoma - 
Select and explain. 
A. Is often associated with hypothyroidism, B. Often produces hyperthyroidism, C. Is usually euthyroid, D. Occurs in toxic nodules
C: Is usually euthyroid
Answer: C: Is usually euthyroid 
Explanation: None