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: Pharmacology
[{'content': 'The following drug is NOT useful during acute attack of bronchial asthma: \nSelect and explain. \nA. Salbutamol, B. Hydrocoisone, C. Cromolyn sodium, D. Theophylline', 'role': 'user'}, {'content': 'Answer: C \nExplanation: drugs used in an acute attack of asthma a) hydrocoisone b)salbutamol c)oxygen d)antibiotic (intensive), IV theophylline cromolyn sodium, nedocromil-mast cell stabilizers are used in chronic asthma ESSENTIALS OF MEDICAL PHARMACOLOGY SEVENTH EDITION KD TRIPATHI PG NO.233', 'role': 'assistant'}]