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': 'Laser Doppler flowmetry is a method used to assess blood flow in \nSelect and explain. \nA. Microvascular systems, B. Microlymphatics, C. Micro vesicles, D. Micro spaces', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]