Final answer:
The proportion of blood pumped out of the left ventricle with each beat, or the ejection fraction, is typically between 55-70%, with about 60% of the blood being ejected, matching option (b) 60%.
Step-by-step explanation:
The proportion of blood pumped out of the left ventricle with each beat is known as the ejection fraction. This is calculated by dividing the stroke volume (SV), which is the amount of blood pumped from the left ventricle with each beat, by the end-diastolic volume (EDV), which is the total volume of blood in the ventricle before it contracts. The SV is normally in the range of 70-80 mL and since the ventricular systole begins with an EDV of approximately 130 mL of blood, the ejection fraction is typically between 55-70%. However, as there is still 50-60 mL of blood remaining in the ventricle following contraction, indicating that approximately 60% of the blood is ejected. This aligns with option (b) 60%.