In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Q: Question: The second heart sound coincides with:
Options: <1> End of ventricular diastole. <2> End of atrial diastole. <3> Opening of the aortic valve. <4> Atrial systole <5> Closing of the semilunar valves.
A:
5