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
Role of 2, 3 DPG in hemoglobin - 
Select and explain. 
A. Unloading oxygen to tissues, B. Increased affinity for oxygen, C. Buffering capacity, D. Osmotic fraglity
A: Unloading oxygen to tissues
Answer: A: Unloading oxygen to tissues 
Explanation: A i.e. Unloading oxygen to tissues