<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:An 8-year-old boy presents to your office for a routine well-child visit. Upon physical examination, he is found to have a harsh-sounding, holosystolic murmur that is best appreciated at the left sternal border. The murmur becomes louder when you ask him to make fists with his hands. Which of the following is the most likely explanation for these findings?? A: Aortic stenosis, B: Tricuspid atresia, C: Pulmonary hypertension, D: Ventricular septal defect, E: Left ventricular hypertrophy,  <response>: This is a question about interpreting cardiac murmurs in a pediatric patient. The key findings are a holosystolic murmur at the left sternal border that increases in intensity with a handgrip maneuver. A holosystolic murmur indicates blood flowing from a high pressure to a low pressure chamber during systole. The location at the left sternal border suggests an origin from the left side of the heart. A murmur that increases with handgrip is characteristic of a ventricular septal defect VSD. Aortic stenosis would cause an ejection systolic murmur. Tricuspid atresia and pulmonary hypertension would not cause a murmur at this location. Left ventricular hypertrophy could cause the murmur but would not increase with handgrip.D: Ventricular septal defect 