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': 'Iris bombe occurs is: \nSelect and explain. \nA. Ring synechiae, B. Anterior synechiae, C. Posterior synechiae, D. All', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Ring synechiae', 'role': 'assistant'}]