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': 'The commonest site of thrombosis is ? \nSelect and explain. \nA. Vein, B. Aery, C. Hea, D. Capillary', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Vein o Aerial thrombosis is much less common than venous thrombosis.", 'role': 'assistant'}]