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: Pharmacology
Depression occurs as a side effect due to the use of: 
Select and explain. 
A. Reserpine, B. Propranolol, C. Morphine, D. Amphetamine
A: Reserpine
Answer: A: Reserpine 
Explanation: None