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': 'An antiepileptic drug used in petitmal epilepsy is: \nSelect and explain. \nA. Phenobarbitonse, B. Dilantoin sodium, C. Dilantoin sodium, D. Ethosuximide', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]