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: Surgery
[{'content': 'What is the best route for total parenteral nutrition? \nSelect and explain. \nA. Brachial vein, B. Femoral vein, C. Saphenous vein, D. Subclavian vein', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Subclavian vein is considered as best route because the catheter lies flat on chest wall.', 'role': 'assistant'}]