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': 'Pulp core contains \nSelect and explain. \nA. Undifferentiated cells, B. Nerve bundles, C. Large vessels, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]