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
All of the following are used to measure ECF volume, excepta) Sucroseb) Sodium chloridec) Inulind) Heavy water 
Select and explain. 
A. c, B. d, C. ab, D. bd
C: ab
Answer: C: ab 
Explanation: Indicators used for fluid volumes
1.       Total body water (TBW)- Deuterium Oxide D2O, Tritium oxide, Aminopyrine, Antipyrine
2.       ECF- Inulin, Sucrose, Mannitol, Sodium thiosulphate, Na22
3.       Plasma volume- Evan’s blue, radioactive iodine labelled serum albumin (I125)
 
4.       Blood cell volume- Cr51 labelled RBC