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: Physiology
[{'content': 'The largest fraction of the total body fluid is: \nSelect and explain. \nA. Extracellular fluid, B. Intracellular fluid, C. Plasma, D. Whole blood', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]