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: Psychiatry
Withdrawal of which of the following causes piloerecton? 
Select and explain. 
A. Morphine, B. Cannabis, C. Smoking, D. Alcohol
A: Morphine
Answer: A: Morphine 
Explanation: Ans. A. MorphineManifestations of morphine withdrawalLacrimationAnxiety & fearSweatingRestlessness rYawningGooseflash (Piloerection).