This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': "Birbeck's granules in the cytoplasm are seen in \nSelect and explain. \nA. Langerhan's cells, B. Mast cell, C. Myelocytes, D. Thrombocytes", 'role': 'user'}, {'content': 'Answer: A \nExplanation: ref Robbins 9/e p622 Birbeck granules, also known as Birbeck bodies, are rod shaped or "tennis-racket" cytoplasmic organelles with a central linear density and a striated appearance. First described in 1961 (where they were simply termed "characteristic granules"), they are solely found in Langerhans cells.', 'role': 'assistant'}]