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: Ophthalmology
[{'content': 'Vossius ring occurs in \nSelect and explain. \nA. Lens dislocation, B. Concussion injury, C. Penetrating injury, D. Extra capsular extraction', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Concussion injury', 'role': 'assistant'}]