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
Pheochromocytoma is a tumour of the: 
Select and explain. 
A. Adrenal cortex, B. Parathyroids, C. Pituitary, D. None of the above
D: None of the above
Answer: D: None of the above 
Explanation: Most adrenal medullary tumors (pheochromocytomas) secrete norepinephrine or epinephrine or both and produce sustained hypertension.
Pheochromocytoma is a tumour of the adrenal medulla.
Reference: Ganong’s Review of Medical Physiology T W E N T Y - F I F T H   E D I T I O N page no 356