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 most common is 
Select and explain. 
A. Sickle cell disease, B. Hereditary spherocytosis, C. G6PD deficiency, D. Cyanotic heart disease
A: Sickle cell disease
Answer: A: Sickle cell disease 
Explanation: All of the above causes Hair on end appearance.
Thalassemia major > Sickle cell disease.
No Thalassemia major in Options.