This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Pharmacology
Which does not act by blocking NMDA receptors- 
Select and explain. 
A. Methoxetamine, B. Methadone, C. Ketamine, D. Diltiazem
D: Diltiazem
Answer: D: Diltiazem 
Explanation: Ans. is 'd' i.e., Diltiazem o Drugs acting bv blocking NMD A receptors are:i) Methoxetamineii) Methadoneiii) Felbamateiv) Acamprostv) Ketaminevi) Phencyclidinevii) Dizocilpineviii) Dextropropoxypheneix) Tramadolx) Pethidinexi) Atomoxetinexii) Nitrous oxide