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': 'Soft contact lenses are made of: \nSelect and explain. \nA. Polymethyl methacrylate, B. Hydroxymethyl methacrylate, C. Glass, D. Silicone', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Hydroxymethyl methacrylate', 'role': 'assistant'}]