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: Dental
One of the most common side effects of phenytoin is 
Select and explain. 
A. Gingival Hyperplasia, B. Gingival Necrosis, C. Dental stains, D. Hypertension
A: Gingival Hyperplasia
Answer: A: Gingival Hyperplasia 
Explanation: None