This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lens, Subject name: Ophthalmology
[{'content': 'Foldable lesn is made up of - \nSelect and explain. \nA. PMMA, B. Silicon, C. Hydrogel, D. None', 'role': 'user'}, {'content': 'Answer: B \nExplanation: (IOL are made of (i) PMMA (ragid IOL); (ii) Silicon, acrylic, hydrogel, collamer (foldable IOL). Ref: Khurana 7th/e p.213 & 4th/e p.195)', 'role': 'assistant'}]