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 histological show – 
Select and explain. 
A. Papillomatosis, B. Marked acanthosis, C. Hypermelanosis, D. All of the above
A: Papillomatosis
Answer: A: Papillomatosis 
Explanation: Histopathologically papillomatosis is characteristically seen in acanthosis nigricans. However, there is no hypermelanosis and there is only mild acanthosis if present.