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 nigrans is most common due to carcinoma of: \nSelect and explain. \nA. Bronchus, B. Breast, C. Colon, D. Testis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Bronchus', 'role': 'assistant'}]