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
A patient with grandmal epilepsy would likely be under treatment with: 
Select and explain. 
A. Meprobamate, B. Pentobarbital, C. Trimethadione, D. Phenytoin
D: Phenytoin
Answer: D: Phenytoin 
Explanation: None