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
Which one of the following does NOT present antigens? 
Select and explain. 
A. NK cells (Natural killer cells), B. Dendritic cells, C. Langerhan's cells, D. Macrophages
A: NK cells (Natural killer cells)
Answer: A: NK cells (Natural killer cells) 
Explanation: None