This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
[{'content': 'Which of the following is NOT a MAO inhibitor? \nSelect and explain. \nA. Tranylcypromine, B. Isocarboxazide, C. Phenelzine, D. Maprotiline', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Maprotiline is not an MAO inhibitor whereas the rest three are. Ref: KD Tripathi 8th ed.', 'role': 'assistant'}]