This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Anatomy
[{'content': 'In langerhans cell hystiocytosis,the characteristic abnormality seen on microscopy is: \nSelect and explain. \nA. Birbecks granules, B. Foamy macrophages, C. Giant cells, D. Plasma cells', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Langerhans cell histiocytosis is characterised by the presence of Birbeck granules in the cytoplasm.(ref Robbins 9th/622)', 'role': 'assistant'}]