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
Which of the following anti-epileptic agents causes the reversible side-effect of gingival hyperplasia? 
Select and explain. 
A. Ethosuximide, B. Phenobarbitone, C. Sodium valproate, D. None of the above
D: None of the above
Answer: D: None of the above 
Explanation: None