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': 'Concussion implies luxation injury \nSelect and explain. \nA. Without displacement and normal mobility, B. Without displacement and increased mobility, C. Displacement in an apical direction, D. Displacement in a coronal direction', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]