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
The side effect of phenytoin when its plasma concentration is above therapeutic level is : 
Select and explain. 
A. Ataxia, B. Gum hypertrophy, C. Osteomalacia, D. Hirsutism
A: Ataxia
Answer: A: Ataxia 
Explanation: None