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: Medicine
[{'content': 'A 50 year old man presented with orbital mass. Systemic examination revealed anaemia and investigations revealed hypergammaglobulinemia. The patient should be investigated to rule out: - \nSelect and explain. \nA. Squamous cell carcinoma, B. Optic nerve glioma, C. Multiple myeloma, D. Malignant melanoma', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]