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
[{'content': 'Osmolality of plasma is mainly contributed by \nSelect and explain. \nA. Glucose, B. Sodium, C. Urea, D. Uric acid', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]