A Well-Trained Athlete Has Prepared to Run in the Boston

A well-trained athlete has prepared to run in the Boston marathon.Your purpose is to study how this athlete's cardiovascular system adapts to the strenuous demands of the race.Assume that just before the athlete runs,measurements of heart rate (60 beats/minute) ,blood pressure (110/80 mm Hg) ,and cardiac output (4.2 L/minute) are recorded. Estimate the athlete's stroke volume.

A) 42 mL
B) 55 mL
C) 70 mL
D) 82 mL
E) 90 mL