This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Body fluid compaments, Subject name: Physiology
[{'content': 'Major ions in ECF are: \nSelect and explain. \nA. Sodium and phosphate, B. Potassium and chloride, C. Sodium and chloride, D. Potassium and phosphate', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]