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: Pathology
[{'content': 'Beta microglobulin is derived from: \nSelect and explain. \nA. B-cells, B. T-cells, C. Both, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: B-cells', 'role': 'assistant'}]