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
Which of the following is the best parameter to assess fluid intake in a polytrauma patient: March 2011 
Select and explain. 
A. Urine output, B. Blood pressure, C. Pulse, D. Pulse oximtery
A: Urine output
Answer: A: Urine output 
Explanation: Ans. A: Urine output