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
[{'content': 'Which of the following drug DOES NOT cause megaloblastic anemia? \nSelect and explain. \nA. Phenytoin, B. Chloroquine, C. Sulfasalazine, D. Metformin', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Agents implicated in drug induced macrocytic anemia are: Phenytoin Azathioprine Metformin Leflunomide Sulfisoxazole Sulfasalazine Mesalamine Zidovudine Trimethoprim Sulfamethoxazole', 'role': 'assistant'}]