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 characteristically seen in \nSelect and explain. \nA. Thalasemia major, B. Sickle cell anaemia, C. G 6PD deficiency, D. Hereditary spherocytosis", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a (Thalassemia major) (Ref. Radiology Review Manual, 5th/pg.174)Causes of "hair on end" or "crew hair cut" skull are# Thalassemia (Characteristic)# Hereditary spherocytosis# Sickle cell disease# G-6-PD deficiency# Iron deficiency anaemia# Neuroblastoma', 'role': 'assistant'}]