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
Drugs associated with gingival changes are: 
Select and explain. 
A. Phenytoin, cystine and nifedipine, B. Nifedipine, ibuprofen and Lignocaine, C. Cyctosporin, chlorine and iodine, D. Phenytoin, hydrogen, hydrogen peroxide and paracetamol
A: Phenytoin, cystine and nifedipine
Answer: A: Phenytoin, cystine and nifedipine 
Explanation: None