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': 'Width of PDL is \nSelect and explain. \nA. 0.10 mm, B. 0.50 mm, C. 0.25 mm, D. 0.75 mm', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]