<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 1-day-old infant in the general care nursery, born at full term by uncomplicated cesarean section delivery, is noted to have a murmur, but otherwise appears well. On examination, respiratory rate is 40min and pulse oximetry is 96. Precordium is normoactive. With auscultation, S1 is normal, S2 is single, and a 26 systolic ejection murmur is heard at the left upper sternal border. Echocardiography shows infundibular pulmonary stenosis, overriding aorta, ventricular septal defect and concentric right ventricular hypertrophy. Which of the following correlate with the presence or absence of cyanosis in this baby?? A: The degree of right ventricular outflow tract obstruction, B: The ratio of reduced hemoglobin to oxyhemoglobin, C: The size of ventricular septal defect, D: The concentration of pulmonary surfactant, E: The concentration of hemoglobin,  <response>: This is a question about cyanotic congenital heart disease in a newborn infant. The stem describes physical exam and echocardiogram findings consistent with tetralogy of Fallot. The choices list various factors that may correlate with the presence or absence of cyanosis. Choice A is correct because the degree of right ventricular outflow tract obstruction affects the amount of deoxygenated blood shunting right-to-left through the ventricular septal defect, which determines whether the infant will be cyanotic. Choice B is irrelevant. Choice C is incorrect because the size of the VSD does not necessarily correlate with cyanosis. Choice D is unrelated to cyanosis. Choice E is incorrect because total hemoglobin concentration alone does not determine cyanosis.A: The degree of right ventricular outflow tract obstruction 