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: Pathology
Increased levels of haemoglobin A2 is characteristic of 
Select and explain. 
A. Sickle cell trait, B. Beta-Thalassaemia trait, C. Glucose-6-phosphate dehydrogenase deficiency, D. Alpha-Thalassaemia
B: Beta-Thalassaemia trait
Answer: B: Beta-Thalassaemia trait 
Explanation: None