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
Phenytoin is associated with: 
Select and explain. 
A. Folic acid deficiency, B. Alzhiemer's disease, C. Cushing's syndrome, D. Vitamin C deficiency
A: Folic acid deficiency
Answer: A: Folic acid deficiency 
Explanation: None