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: Dental
Acanthosis Nigricans in old pt. Usually indicate – 
Select and explain. 
A. Skin disorder, B. Malignancy, C. Senile brain, D. Usually found in negro
B: Malignancy
Answer: B: Malignancy 
Explanation: None