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
Breast feeding is contraindicated if the mother is taking: 
Select and explain. 
A. Iron tonics, B. Iron tonics, C. Crystalline penicillin, D. Phenytoin
D: Phenytoin
Answer: D: Phenytoin 
Explanation: Phenytoin