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: Pathology
[{'content': 'S100 is a marker for: \nSelect and explain. \nA. Melanoma, B. Schwannoma, C. Histiocytoma, D. Hemangioma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Melanoma', 'role': 'assistant'}]