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': 'Which of the following is the best parameter to assess fluid intake in a polytrauma patient: March 2011 \nSelect and explain. \nA. Urine output, B. Blood pressure, C. Pulse, D. Pulse oximtery', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A: Urine output', 'role': 'assistant'}]