This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Arterial Disorders, Subject name: Surgery
[{'content': 'A 82-year-old female presented with history of loss of vision in right eye for about 15 minutes and it cleared up. She has a history of diabetes and hypertension. She had which showed old infarct on right side. Carotid duplex showed that patient had 99% carotid artery stenosis. Which one of the following statements is TRUE? \nSelect and explain. \nA. 60%chance that extra cranial carotid artery stenosis is the cause of transient ischemic attack (TIA), B. It is always due to platelet emboli., C. 25% may be intracranial bleed., D. 0.5 to 10% may have cardiac and other causes of TIA.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Neurological events are associated with extracranial carotid artery in about 60%. Forty percent may have extracranial/intracranial cause for neurological events, which includes cardiac emboli, arch of aorta as source of emboli; intracranial bleed may be more than just a TIA. It is not always that platelet emboli are the cause of TIA, it could be due to atheroma. It is not always attributed to thrombus.', 'role': 'assistant'}]