This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
[{'content': "ECF volume is best evaluated by \nSelect and explain. \nA. Mannitol, B. Inulin, C. D2O, D. Evan's blue", 'role': 'user'}, {'content': 'Answer: B \nExplanation: ECF volume is measured by inulin which is a polysaccharide.(Ref: Textbook of physiology N Geetha 2nd edition page no.61)', 'role': 'assistant'}]