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
A 5 year old girl came with history of progressively increasing pallor since birth and hepatosplenomegaly. Which of the following is the most relevant test for achieving diagnosis - 
Select and explain. 
A. Hb electrophoresis, B. Peripheral smear examination, C. Osmotic fragility test, D. Bone marrow examination
A: Hb electrophoresis
Answer: A: Hb electrophoresis 
Explanation: None