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': "Knudson's hypothesis is applied for: \nSelect and explain. \nA. Glaucoma, B. Retinoblastoma, C. Cataract, D. Melanoma", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Retinoblastoma', 'role': 'assistant'}]