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': 'The most potent stimulator of naive ? cells is: \nSelect and explain. \nA. ? cell, B. Mature dendritic cells, C. Epithelial cells, D. Macrophages', 'role': 'user'}, {'content': 'Answer: B \nExplanation: . Mature dendritic cells', 'role': 'assistant'}]