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': 'Valproic acid causes all except: \nSelect and explain. \nA. It is an enzyme inducer, B. It causes obesity, C. It causes hepatotoxicity, D. It causes neural tube defects', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]