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
O2 dissociation curve shift to right in all except 
Select and explain. 
A. Diabetic ketoacidosis, B. Blood transfusion, C. High altitude, D. Anaemia
B: Blood transfusion
Answer: B: Blood transfusion 
Explanation: None