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
All are used In bronchial asthma, except 
Select and explain. 
A. Salbutamol, B. Morphine, C. Aminophylline, D. Steroid
B: Morphine
Answer: B: Morphine 
Explanation: 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.