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': 'In considering the process of eruption, the pre-functional eruptive stage of a tooth begins when the: \nSelect and explain. \nA. Bud stage begins, B. Cap stage begins, C. Bell stage begins, D. Dental lamina begins forming', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The dental lamina serves as the primordium of ectodermal portion of deciduous teeth. The permanent molars arise directly from a distal extension of dental lamina.', 'role': 'assistant'}]