This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'A two–year old boy present with episodes of becoming dusky. On examination, there was central cyanosis and clubbing. There was no pallor, oedema or respiratory distress. The heart was normal sized with a parasternal heave. A systolic thrill was palpable over the left middle sternal border. First heart sound was normal and only the aortic component was audible in the second heart sound. Liver was not enlarged – What would be the likely diagnosis – \nSelect and explain. \nA. Congenital methemoglobinemia, B. Eisenmenger syndrome, C. Aortic stenosis, D. Tetralogy of Fallot', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Features in this child suggestive of TOF : -\n\n\nCyanosis at 2 year (not at birth)\nNo pallor, dysnea or edema —> No CHF\nNormal sized heart\n\n\nThese features suggest the diagnosis of TOF.\nThese have been explained earlier.', 'role': 'assistant'}]