This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Physiology
The type of hemoglobin that has least affinity for 1, 3- Diphosphoglycerate (2,3-DPG) or (2, 3-BPG) is 
Select and explain. 
A. Hg A, B. Hg F, C. HB, D. Hg A2
B: Hg F
Answer: B: Hg F 
Explanation: Fetal hemoglobin has least affinity for 13diphosphoglycerate Ref: guyton and hall textbook of medical physiology 12 edition page number: 312,313,314