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': 'Clinical signs of occlusal trauma include all except: \nSelect and explain. \nA. Periodontal pockets, B. Migration of teeth, C. Tenderness on percussion, D. Increased width of periodontal ligament', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]