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
Extremely lethal among all thyroid tumors is: 
Select and explain. 
A. Medullary carcinoma., B. Papillary carcinoma., C. Anaplastic carcinoma., D. Follicular carcinoma.
C: Anaplastic carcinoma.
Answer: C: Anaplastic carcinoma. 
Explanation: None