<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 9-year-old boy is brought to the office due to exertional dyspnea and fatigability. He tires easily when walking or playing. His parents say that he was diagnosed with a congenital heart disease during his infancy, but they refused any treatment. They do not remember much about his diagnosis. The patient also had occasional respiratory infections throughout childhood that did not require hospitalization. He takes no medications. The patient has no family history of heart disease. His vital signs iclude: heart rate 98min, respiratory rate 16min, temperature 37.2C 98.9F, and blood pressure of 11080 mm Hg. Physical examination shows toe cyanosis and clubbing but no finger abnormalities. Cardiac auscultation reveals a continuous machine-like murmur. All extremity pulses are full and equal. Which of the following is the most likely diagnosis?? A: Atrial septal defect, B: Coarctation of the aorta, C: Patent ductus arteriosus, D: Tetralogy of Fallot, E: Ventricular septal defect,  <response>: Based on the information provided in the question stem, the key findings are:- 9 year old boy with exertional dyspnea and fatigability - History of congenital heart disease diagnosed in infancy but no treatment- Occasional respiratory infections in childhood - Vital signs show tachycardia and clubbing of toes but no finger abnormalities- Continuous machine-like murmur on cardiac auscultation- Full and equal extremity pulsesThese findings are most consistent with a diagnosis of patent ductus arteriosus PDA. The continuous murmur points to a structural defect allowing continuous blood flow between major arteries or cardiac chambers. The full pulses make coarctation of the aorta unlikely. The lack of cyanosis and heart failure symptoms make a septal defect less likely. The lack of cyanosis and polycythemia makes tetralogy of Fallot unlikely. Overall, the clinical picture fits with a PDA.C: Patent ductus arteriosus 