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': 'Biobrane is a commercially available: \nSelect and explain. \nA. Root matrix protein, B. Biodegradable membrane, C. Bone graft material, D. Non-bone graft material', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]