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
[{'content': 'Drugs associated with gingival changes are: \nSelect and explain. \nA. Phenytoin, cystine and nifedipine, B. Nifedipine, ibuprofen and Lignocaine, C. Cyctosporin, chlorine and iodine, D. Phenytoin, hydrogen, hydrogen peroxide and paracetamol', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]