<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 16-year-old boy is brought to the physician by his parents because of a 6-month history of progressive fatigue and worsening shortness of breath on exertion. The parents report that the boy has always been tired out a bit more easily than other kids. The family recently immigrated to the United States from rural South Korea. Pulse oximetry on room air shows an oxygen saturation of 96 on bilateral index fingers. Radial pulses are bounding. There is mild bluish discoloration and bulbous enlargement of the distal toes bilaterally. Echocardiography is most likely to show which of the following?? A: Single overriding great vessel arising from the heart, B: Anomalous shunting of blood through a defect in atrial septum, C: Persistent blood flow between the pulmonary artery and descending aorta, D: Positioning of the ascending aorta directly over a ventricular septal defect, E: Abnormal narrowing of the aorta at the aortic isthmus,  <response>: This is a clinical vignette describing a 16-year-old boy with a 6-month history of progressive fatigue, shortness of breath on exertion, and mild clubbing and cyanosis of the distal toes bilaterally. The key findings are fatigue, dyspnea on exertion, oxygen saturation of 96, bounding radial pulses, and clubbingcyanosis of the toes. This suggests some form of right-to-left shunting congenital heart disease.Choice A describes a single great vessel arising from the heart, which would not explain the clinical findings. Choice B describes an atrial septal defect, which could cause right-to-left shunting and the described symptoms. However, an ASD would likely cause more significant desaturation.Choice C describes patent ductus arteriosus, which could also cause right-to-left shunting and potentially explain the symptoms and mild desaturation. This is a reasonable choice.Choice D describes a ventricular septal defect with aortic override, which does not fit with the predominantly right-sided findings. Choice E describes coarctation of the aorta, which would not explain right-to-left shunting or the clinical findings.Based on the mild desaturation and clinical findings consistent with right-to-left shunting, choice C patent ductus arteriosus seems the most likely diagnosis.C: Persistent blood flow between the pulmonary artery and descending aorta 