This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Pediatrics
[{'content': 'A child with three days history of upper respirotory tract infection presents with stridor, which decreases on lying down postion. What is the most probable diagnosis \nSelect and explain. \nA. Acute Epiglottitis, B. Laryngotracheobronchitis, C. Foreign body aspiration, D. Retropharyngeal abscess', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Biphasic stridor usually originates from subglottic or proximal tracheal lesions. laryngotracheobranchitis presents in children of 1-5 years of age with biphasic stridor,brassy cough&low grade fever. Ref : Essential Paediatrics,O.P.Ghai,7 th edition,Pg No:339', 'role': 'assistant'}]