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: Pathology
[{'content': 'Commonest cause of Cerebral Infarction is: \nSelect and explain. \nA. Aerial thrombosis, B. Aeritis, C. Venous thrombosis, D. Lymphangitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Aerial thrombosis', 'role': 'assistant'}]