This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
[{'content': 'Investigation of choice to diagnose hyperophic pyloric Stenosis in infants is \nSelect and explain. \nA. Contrast radiology, B. Gastroscopy, C. Ultrasound abdomen, D. CT scan abdomen', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ultrasonography is recommended because its sensitivity and specificity are close to 100% for this disease. Ultrasound is reliable and easily performed and has replaced barium studies as the main investigation.There is a normal variation of pylorus muscle measurements with age and gestation but ultrasound has a very high sensitivity and specificity.', 'role': 'assistant'}]