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': 'Which of the following is not a bronchodilator \nSelect and explain. \nA. Beta 2 agonist, B. Methylxanthines, C. Steroids, D. Anticholinergics', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Classification: bronchodilators: beta 2 agonists anticholinergics and methylxanthines like caffeine and theophylline ref KD Tripathi 8th ed', 'role': 'assistant'}]