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: Dental
[{'content': 'Decalcified freeze-dried bone graft is an example of \nSelect and explain. \nA. Xenograft, B. Autograft, C. Alloplast, D. Allograft', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]