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': 'Severity of Aortic stenosis is determined by ?a) Late ejection systolic murmurb) ST –T changesc) LV Hypertrophy with displaced apexd)  None \nSelect and explain. \nA. ac, B. ab, C. ad, D. bc', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]