This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Body fluid compaments, Subject name: Physiology
[{'content': 'D2O is used to determine- \nSelect and explain. \nA. ICF, B. ECF, C. Total body water, D. Plasma volume', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Volume Indicators Total body water 3H2O, 2H2O, Antipyrine Extracellular fluid 22Na, 125I-iothalamate, thiosulphate, inulin ICF (calculated as TBW-ECF) Plasma volume 125I-albumin, Evans blue dye Interstitial fluid (calculated as ECF-plasma volume) Blood volume Cr-labeled red blood cells', 'role': 'assistant'}]