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': 'Each of the following drug regimens is likely to influence periodontal treatment planning EXCEPT \nSelect and explain. \nA. Dexamethasone, B. Dicoumarol, C. Diphenhydramine, D. Nitroglycerine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]