This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluid & Electrolyte, Subject name: Pediatrics
What percentage of body weight of a one year old child is TBW? 
Select and explain. 
A. 90%, B. 80%, C. 60%, D. 40%
C: 60%
Answer: C: 60% 
Explanation: Ans. is 'c' i.e., 60% * Total body water (TBW) as a percentage of body weight declines form as high as 90% in early fetal life to 75- 80% at birth. Thereafter it declines progressively to 60% by the end of one year. After that it remains constant.