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
Ejection fraction is about 
Select and explain. 
A. 25%, B. 45%, C. 55%, D. 65%
D: 65%
Answer: D: 65% 
Explanation: The ejection fraction, the percent of the end-diastolic ventricular volume that is ejected with each stroke, is about 65%. The ejection fraction is a valuable index of ventricular function.