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
Shift of the oxygen dissociation curve to right is caused by the following factors EXCEPT 
Select and explain. 
A. Increased 2, 3, BPG, B. Increased temperature, C. Increased concentration of carbon-di-oxide, D. Increased concentration of oxygen
D: Increased concentration of oxygen
Answer: D: Increased concentration of oxygen 
Explanation: None