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: Skin
[{'content': 'Acanthosis Nigricans in old patient usually indicate : \nSelect and explain. \nA. Skin Disorder, B. Malignancy, C. Senile Brain, D. Usually found in negro', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B. i.e. Malignancy', 'role': 'assistant'}]