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': 'The most common etiology of posterior staphyloma is ? \nSelect and explain. \nA. Trauma, B. Glaucoma, C. Degenerative axial myopia, D. Scleritis', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Degenerative axial myopia", 'role': 'assistant'}]