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
[{'content': 'Least common ion in EOF is \nSelect and explain. \nA. Na, B. K+, C. CI, D. HCO3', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Predominent ions in ECF are Na+ and Cl-predominent ions in ICF are K+ ,Mg+,phosphate Table1.3.3 of Textbook of physiology AK Jain 4th edition page no.27.', 'role': 'assistant'}]