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: Physiology
Calcitonin is released by: 
Select and explain. 
A. Parafollicular cells of thyroid, B. Chief cells of thyroid, C. Granular cells of adrenal gland, D. Stratum fasciculata of adrenal gland
A: Parafollicular cells of thyroid
Answer: A: Parafollicular cells of thyroid 
Explanation: None