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': 'Most common cause of cerebrovascular accident is : \nSelect and explain. \nA. Embolism, B. Aerial thrombosis, C. Venous thrombosis, D. Haemorrhage', 'role': 'user'}, {'content': "Answer: A \nExplanation: Answer is A (Embolism): The most common cause of cerebrovascular accidents is embolism. Harrisons 16th has not classified ischaemic strokes into thrombotic and embolic events but into Atherosclerosis (4%), cardioembolic (17%), & others (64%). Neveheless even others (64%) include most commonly embolic events other than those of cardiac origin such as 'aery to aery embolic strokes' etc. and hence the answer stays the same.", 'role': 'assistant'}]