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
Side effects of phenytoin are : 
Select and explain. 
A. Gum hypertrophy, B. Alopecia, C. Subungal exostosis, D. Onycholysis
A: Gum hypertrophy
Answer: A: Gum hypertrophy 
Explanation: None