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': "A patient's urine with a particular protein appears normal, but on standing it becomes dark. The dark colour disappears on heating. The patient is suffering from \nSelect and explain. \nA. Osteoporosis, B. Multiple myeloma, C. Infectious mononucleosis, D. T  cell tumour", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]