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
2-3 DPG is decreased in ? 
Select and explain. 
A. Anemia, B. Acidosis, C. High altitude, D. Exercise
B: Acidosis
Answer: B: Acidosis 
Explanation: Ans. is 'b' i.e., AcidosisFactors which decrease 2,3 DPG and cause left shift of O2 dissociation curve are :-i) Acidosisii) Stored bloodiii) Fetal hemoglobin