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': 'Reservoir of dividing cells for the growing enamel organ \nSelect and explain. \nA. Temporary structures, B. Enamel knot, C. Enamel cord, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Both enamel knot and enamel cord of stellate reticulum are temporary structures and act as a reservoir dividing cells S the growing enamel organ.', 'role': 'assistant'}]