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 showing brownish pigmentation and with\nnormal laboratory findings may be suffering from: \nSelect and explain. \nA. Addison's disease, B. Fibrous dysplasia, C. Neuro fibromatosis, D. None of the above", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]