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: Pediatrics
Hb A 2 concentration in thalassemia trait is ? 
Select and explain. 
A. 1, B. 1-2.5, C. 2.5-3.5, D. > 3-5
D: > 3-5
Answer: D: > 3-5 
Explanation: Ans. is 'd' i.e.,> 3.5 Nestrof test o This test is being widely used in India and other developing countries in thalassemia screening programmes. o The cases which are positive, subjected to HbA2 estimation for confirmation of thalassemia trait.