This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Physiology
[{'content': "Which of the following is the best for measuring total body water: \nSelect and explain. \nA. Evan's blue, B. I131, C. Tritium oxide, D. P 32", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C. Tritium oxideRadioactive water (TRITIUM) or heavy water (deuterium) can be used to measure total body water. Tritium is also used as a tracer in chemical and biochemical research.', 'role': 'assistant'}]