This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal system, Subject name: Radiology
[{'content': '"Hair-on end" appearance is seen in - \nSelect and explain. \nA. Thalassemia, B. Sickle cell anemia, C. Hemochromatosis, D. Megaloblastic anemia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hair on end skull appearance is seen in the diploic space of skull,having the appearance of long veicle striations. These striations are due to alternating thickened trabeculae and radiolucent marrow hyperplasia seen in following conditions : Thalaseemia Major - Most common and characteristic feature sickle cell anemia Hereditary spherocytosis Severe iron deficiency anemia. Hence the single best answer would be Thalaseemia major', 'role': 'assistant'}]