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
Folic acid deficiency occurs in: 
Select and explain. 
A. Aspirin, B. Phenytoin, C. Chloromphenicol, D. Cyclosporine
B: Phenytoin
Answer: B: Phenytoin 
Explanation: None