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': 'Band-shaped keratopathy is caused by – \nSelect and explain. \nA. Amyloid, B. Calcium, C. Monopolysaccharide, D. Lipid', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Band keratopathy is characterized by the deposition of calcium salts in a band-like pattern in the anterior layers of the cornea.', 'role': 'assistant'}]