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': 'Greatest portion of teeth is formed by: \nSelect and explain. \nA. Enamel, B. Dentin, C. Pulp, D. Cementum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]