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': 'Electronic instrument used to measure gingival crevicular fluid is \nSelect and explain. \nA. Pericheck, B. Periotemp, C. Perioscan, D. Peiotron', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]