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': 'In facia type of facebow, the centre of condylar rotation is arbitrarily marked as____ mm anterior to the middle of the tragus of the ear on canthotragal line. \nSelect and explain. \nA. 10 mm, B. 11 mm, C. 12 mm, D. 13 mm', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Facia type: In the facia type of facebow, the centre of condylar rotation is arbitrarily marked as 13 mm anterior to the middle of the tragus of the ear, on a line drawn from the outer canthus of the eye to the middle of the tragus of the ear – canthotragal line.\nThe condylar rods of the facebow are placed on this point. Unlike the earpiece type, this facebow is mounted by placing the condylar rods at the centre of the condyle in the articulator.', 'role': 'assistant'}]