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: Radiology
Hair on end appearance is characteristically seen in – 
Select and explain. 
A. Thalassemia major, B. Sickle cell anemia, C. G6PD deficiency, D. Hereditary spherocytosis
A: Thalassemia major
Answer: A: Thalassemia major 
Explanation: Hair on end appearance is characteristically and most commonly seen in thalassemia because marrow hyperplasia is more marked in this than other anemia.
Sickle cell anemia is the 2nd most common cause (after thalassemia).