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
Medullary carcinoma thyroid arises from - 
Select and explain. 
A. Parafollicular cells, B. Cells lining the acini, C. Capsule of thyroid, D. Stroma of the gland
A: Parafollicular cells
Answer: A: Parafollicular cells 
Explanation: None