<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 16-year-old boy with a history of severe, persistent asthma presents to the emergency department with severe shortness of breath and cough. He states that he was outside playing basketball with his friends, forgot to take his inhaler, and began to have severe difficulty breathing. On exam, he is in clear respiratory distress with decreased air movement throughout all lung fields. He is immediately treated with beta-agonists which markedly improve his symptoms. Prior to treatment, which of the following was most likely observed in this patient?? A: Inspiratory stridor, B: Increased breath sounds, C: Friction rub, D: Kussmauls sign, E: Pulsus paradoxus,  <response>: This is a clinical vignette about a 16-year-old boy with severe, persistent asthma who presents to the ED in respiratory distress after forgetting to take his inhaler while playing basketball outside. The question asks which physical exam finding was most likely in this patient prior to treatment with beta-agonists. Choice A can be eliminated because stridor is an upper airway obstruction finding, not consistent with asthma. Choice B can be eliminated because asthma causes decreased breath sounds. Choice C can be eliminated because a friction rub suggests pleural inflammation, not seen in asthma. Choice D refers to deep, rapid breathing seen in diabetic ketoacidosis, unrelated to this vignette. Choice E, pulsus paradoxus, is the correct answer. Pulsus paradoxus refers to an exaggeration of the normal decrease in systolic blood pressure during inspiration and is a classic physical exam finding in asthma exacerbations due to increased negative intrathoracic pressure swings.E: Pulsus paradoxus 