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
During exercise increase in 02 delivery to muscles is because of all except : 
Select and explain. 
A. Oxygen dissociation curve shifts to left, B. Increased stroke volume, C. Increased extraction of oxygen from the blood, D. Increased blood flow to muscles
A: Oxygen dissociation curve shifts to left
Answer: A: Oxygen dissociation curve shifts to left 
Explanation: A i.e. Oxygen dissociation curve shifts to left