Use the Following Information to Answer Questions 8 and 9 $\mathrm { D }$

Use the following information to answer Questions 8 and 9. A 50-year-old man has a body weight of 110 kg, resting heart rate of 90 beats/min, arterial pressure of 120/70 mm Hg, arterial hematocrit of 35%, and normal body temperature. His pressure-volume diagram of the left ventricle is shown below.
-When does the fourth heart sound occur in the ventricular pressure-volume relationship?


A. At point $\mathrm { D }$
B. Between point $\mathrm { A }$ and point $\mathrm { B }$
C. Between point $B$ and point $C$
D. Between point $C$ and point $D$
E. Between point $\mathrm { D }$ and point $\mathrm { A }$
Left Ventricular Volume ( $\mathrm { mI } )$