This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiac Output, Subject name: Physiology
A 25-year old athlete has an ejection fraction of 0.50 and an end-systolic volume of 50 mL. What is his end-diastolic volume? 
Select and explain. 
A. 75 mL, B. 100 mL, C. 125 mL, D. 150 mL
B: 100 mL
Answer: B: 100 mL 
Explanation: Ejection fraction = X 100 EDV - SV = ESV (end-systolic volume) If ejection fraction is 0.5 or 50%, it means 50% of the EDV is pumped out as stroke volume; and remaining 50% is left behind as end-systolic volume (ESV). ESV given is 50 mL; so EDV would be 100 mL.