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: Physiology
Fetal hemoglobin has more affinity for oxygen than adult hemoglobin because ? 
Select and explain. 
A. Decreased 2,3 DPG concentration, B. Low affinity for 2,3 DPG, C. Increase 2,3 DPG concentration, D. Reduced pH
B: Low affinity for 2,3 DPG
Answer: B: Low affinity for 2,3 DPG 
Explanation: Ans. is 'b' i.e., Low affinity for 2,3 DPG Make it very clear in mind that higher affinity of fetal hemoglobin for oxygen is due to low affinity of HbF for 2,3DPG (not due to decreased 2, 3-DPG concentration). HbF does not combines to 2, 3-DPG as avidly as adult hemoglobin.