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
Percentage of 02 carried in chemical combination 
Select and explain. 
A. 97%, B. 3%, C. 66%, D. 33%
A: 97%
Answer: A: 97% 
Explanation: A i.e. 97%;