This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
All are seen more in ECF except 
Select and explain. 
A. Na+, B. Cl-, C. Mg++, D. HCO-3
C: Mg++
Answer: C: Mg++ 
Explanation: Na+,Ca+,Cl- and HCO3- are largely extracellular whereas K+,Mg2+ are predominantly seen in ICF.(Ref: Textbook of physiology AK Jain 5tg edition page no.27)