The pressures at three moments are given in mm Hg…

Step 1. (a) The atrium ($10$) is above the ventricle ($4$), so the valve between them is open. The ventricle is below the artery ($80$), so the other valve is shut. Blood fills the ventricle.

Step 2. (b) The ventricle ($95$) is above the atrium ($3$), so the valve between them is shut. It is also above the artery ($80$), so the semilunar valve is open. Blood is pumped out.

Step 3. (c) The ventricle ($40$) is above the atrium ($3$), so the first valve is shut. It is below the artery ($80$), so the second valve is shut too. Both valves are shut.