This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
[{'content': 'Which of the following is the approximate extracellular fluid volume of a normal individual? \nSelect and explain. \nA. 5% of body mass, B. 10% of body mass, C. 20% of body mass, D. 40% of body mass', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Sixty percent of the body mass is water. Of this water, one-third (20% of body mass) is extracellular and two-thirds (40% of body mass) is intracellular.The extracellular water is fuher divided into interstitial water (80% of the extracellular fluid, or 15% of body mass) and plasma water (20% of the extracellular fluid, or 5% of body mass).The percentage of water in the body is a function of body fat. The greater the percentage of body fat, the lower the percentage of body water.', 'role': 'assistant'}]