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
[{'content': 'Acanthosis nigricans histological show – \nSelect and explain. \nA. Papillomatosis, B. Marked acanthosis, C. Hypermelanosis, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Histopathologically papillomatosis is characteristically seen in acanthosis nigricans. However, there is no hypermelanosis and there is only mild acanthosis if present.', 'role': 'assistant'}]