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': 'Length of C.P.I.T.N. probe is \nSelect and explain. \nA. 14.0 mm, B. 13.0 mm, C. 11.5 mm, D. 12.5 mm', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]