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': 'Most impoant HLA for organ transplantation and tissue typing - \nSelect and explain. \nA. HLA-A, B. HLA-B, C. HLA-C, D. HLA-D', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., HLA-D", 'role': 'assistant'}]