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: Forensic Medicine
[{'content': 'Risk of thromboembolism is highest with: DNB 08 \nSelect and explain. \nA. Deep femoral vein thrombus, B. Anterior tibial vein thrombus, C. Posterior tibial vein thrombus, D. Popliteal vein thrombus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Deep femoral vein thrombus', 'role': 'assistant'}]