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: Physiology
[{'content': 'Which of the following increases turbulence in blood flow? \nSelect and explain. \nA. Reynolds number< 2000, B. Decrease in velocity of blood, C. Decrease in density of blood, D. Increase in diameter of blood vessel', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]