<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 2-year-old boy is brought to the physician by his father for a well-child examination. He recently emigrated from Mexico with his family and has not seen a physician since birth. Vital signs are within normal limits. Cardiac examination shows a harsh, grade 36 holosystolic murmur heard best at the left lower sternal border. During deep inspiration, the second heart sound is split. If left untreated, irreversible changes would most likely be seen in which of the following structures?? A: Right atrium, B: Ascending aorta, C: Superior vena cava, D: Pulmonary artery, E: Mitral valve,  <response>: This is a clinical vignette about a 2-year-old boy with a heart murmur on cardiac exam. The key findings are a harsh, grade 36 holosystolic murmur at the left lower sternal border and split S2 on inspiration. These findings are classic for ventricular septal defect VSD. A VSD causes increased blood flow and pressure overload on the pulmonary vasculature over time. If left untreated, irreversible changes would occur in the pulmonary arteries due to pulmonary hypertension.D: Pulmonary artery 