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: Medicine
Hemoglobin electrophoresis is used as confirmatory test in which of the following anemias? 
Select and explain. 
A. Iron deficiency anemia, B. Polycythemia, C. Hereditary spherocytosis, D. Sickle cell anemia
D: Sickle cell anemia
Answer: D: Sickle cell anemia 
Explanation: None