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': 'Tooth mobility is NOT reversible when there is \nSelect and explain. \nA. Inflammation in periodontium, B. Trauma from occlusion, C. Loss of alveolar bone, D. Faulty tooth brushing technique', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]