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: Surgery
[{'content': 'Graft from sister to brother is - \nSelect and explain. \nA. Isograft, B. Allograft, C. Autograft, D. Heterograft', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Allograft", 'role': 'assistant'}]