This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Hyperpigmentation, Subject name: Skin
[{'content': 'Pigmented lesion in mouth and not in skin - \nSelect and explain. \nA. Cushing syndrome, B. Addison disease, C. Peutz Jegers, D. None of the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., None of the above o All of them are associated with oral as well as skin pigmentation.", 'role': 'assistant'}]