The diagram illustrates how pressure in the left side of the heart and the aorta varies during this cardiac cycle, which lasts $0.6\,\text{s}$. Points 1, 2, 3 and 4 show the moments when the atrio-ventricular valves and semi-lunar valves open or close. What is the total duration in one cardiac cycle for which both the atrio-ventricular valves and the semi-lunar valves are closed at the same time?
- A$0.03\,\text{s}$
- B$0.04\,\text{s}$
- C$0.07\,\text{s}$
- D$0.21\,\text{s}$