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
Serum calcitonin is a marker for 
Select and explain. 
A. Anaplastic carcinoma, B. Papillary carcinoma, C. Medullary carcinoma, D. Follicular carcinoma
C: Medullary carcinoma
Answer: C: Medullary carcinoma 
Explanation: None