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': 'If the radius of dentinal tubule is halved, the flow rate will decrease by: \nSelect and explain. \nA. 2 times, B. 4 times, C. 8 times, D. 16 times', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Flow rate is a function of tubule diameter,pulpal pressure difference,viscosity and tubule length.\xa0\nA two fold reduction which means making it half, results in a 16 fold reduction as per the formula.', 'role': 'assistant'}]