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: Pathology
[{'content': 'In sickle cell anemia, the defect is in which chain - \nSelect and explain. \nA. α-chain, B. β-chain, C. Both the chains, D. None of these', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]