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': "Which one of the following does NOT present antigens? \nSelect and explain. \nA. NK cells (Natural killer cells), B. Dendritic cells, C. Langerhan's cells, D. Macrophages", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]