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
All of the following are hallucinogens, except - 
Select and explain. 
A. LSD, B. Phenylcyclidine, C. Mescaline, D. Methylphenidate
D: Methylphenidate
Answer: D: Methylphenidate 
Explanation: Ans. is 'd' i.e., Methylphenidate