Figure 20-2 Cardiac Cycle

Use Figure 20-2 to answer the following questions:
-What is occurring in the left atrium at the circle labeled "2" on the graph?

A) Left atrium is pressurizing the left ventricle.
B) Left atrium is in systole.
C) Left atrial pressure is decreasing.
D) Left atrium is in diastole.
E) Left atrium is receiving pressure from the left ventricle.