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: Medicine
[{'content': 'All are used In bronchial asthma, except \nSelect and explain. \nA. Salbutamol, B. Morphine, C. Aminophylline, D. Steroid', 'role': 'user'}, {'content': "Answer: B \nExplanation: Salbutamol is a beta2 agonist which relaxes smooth muscles and relieves bronchospasm.Aminophylline is a phosphodiesterase inhibitor that produces bronchodilator effect along with anti-inflammatory effect.Steroids,both oral and inhalational,are also used in asthma because of their anti-inflammatory propey. WHO proposed step wise approach for management of bronchial asthma. Morphine is used in emergency management of acute myocardial infarction. Reference:Harrison's medicine-18th edition,page no:2110.", 'role': 'assistant'}]