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 characterized by excessive secretion of: 
Select and explain. 
A. Catecholamines., B. Glucocorticoids., C. Aldosterone., D. All of the above.
A: Catecholamines.
Answer: A: Catecholamines. 
Explanation: Pheochromocytoma is the tumour of the adrenal medulla.