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 is an inhibitor of dihydrofolate reductase? \nSelect and explain. \nA. Phenytoin, B. Alcohol, C. Yeast, D. Methotrexate', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Drugs causing folate deficiency', 'role': 'assistant'}]