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': 'Maximum contribution of plasma osmolarity is by \nSelect and explain. \nA. Urea, B. Glucose, C. Sodium, D. Albumin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Sodium is the major contributor plasma osmolarity Ref: guyton and hall textbook of medical physiology 12 edition page number: 50,51,52', 'role': 'assistant'}]