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': "Birbeck granules in the cytoplasm are seen in ? \nSelect and explain. \nA. Mast cells, B. Langerhan's cells, C. Thrombocytes, D. Myelocytes", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Langerhan's cells", 'role': 'assistant'}]