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': 'Early Bell stage differ from advanced Bell stage: \nSelect and explain. \nA. Morphodifferentiation occurs in Early Bell stage and Histodifferentiationoccurs in advanced Bell stage., B. Morphodifferentiation occurs in advanced Bell stage and Histodifferentiation occurs in Early Bell stage., C. Different in Apposition., D. None.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: These are developmental stages of tooth.\nHistodifferentiation occurs in early bell stage white morphodifferentiation occurs in advanced bell stage.', 'role': 'assistant'}]