<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 21-year-old man presents to his physician for a routine checkup. His doctor asks him if he has had any particular concerns since his last visit and if he has taken any new medications. He says that he has not been ill over the past year, except for one episode of the flu. He has been training excessively for his intercollege football tournament, which is supposed to be a huge event. His blood pressure is 11070 mm Hg, pulse is 69min, and respirations are 17min. He has a heart sound coinciding with the rapid filling of the ventricles and no murmurs. He does not have any other significant physical findings. Which of the following best describes the heart sound heard in this patient?? A: Opening snap, B: Fourth heart sound S4, C: Mid-systolic click, D: Second heart sound S2, E: Third heart sound S3,  <response>: This is a question about identifying a heart sound in a healthy young adult male with no significant medical history, who has been exercising excessively. The key details are that he is a 21-year-old male with normal vital signs, no murmurs, and a heart sound coinciding with rapid ventricular filling. The opening snap, mid-systolic click, and second heart sound can be ruled out as they occur in systole, not diastole when the ventricles are rapidly filling. The fourth heart sound occurs later in diastole after the atria contract. By process of elimination, the heart sound coinciding with rapid ventricular filling in this healthy young athlete is most likely the third heart sound S3.E: Third heart sound S3 