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': 'Dentinogenesis by odontoblasts first begins at \nSelect and explain. \nA. Pulpal end, B. Cusp tip, C. Tooth bud stage, D. Cervical area', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]