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': 'Fluid flow in and out of the dentinal tubules is proportional to the tubule diameter by: \nSelect and explain. \nA. Third power of the diameter, B. Sixth power of the diameter, C. Square of diameter, D. Fourth power of diameter', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Fluid flow in dentin tubules follows Poiseuille’s law as all tubular structures:', 'role': 'assistant'}]