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: Medicine
[{'content': 'Lacunar infarcts are caused by - \nSelect and explain. \nA. Lipohyalinosis of penetrating arteries, B. Middle carotid artery involvement, C. Emboli to anterior circulation, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]