Use the Following Information to Answer Questions 5-7

Use the following information to answer Questions 5-7. A 60-year-old woman has a body weight of 110 kg, resting cardiac output of 9000 ml/min, arterial pressure of 90/50 mm Hg, arterial hematocrit of 25%, and normal body temperature. Her pressure-volume diagram of the left ventricle is shown below.
-What event occurs at point A in the woman's pressure-volume relationship?

A) Atrioventricular valves close
B) Aortic valve opens
C) Aortic valve closes
D) Atrioventricular valves open
E) Third heart sound