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': 'Drugs which increase level of Theophylline include \nSelect and explain. \nA. Ciprofloxacin, B. Cimetidine, C. Allopurinol, D. All of the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: Refer KDT 6/e p 221 Drugs which inhibit Theophylline metabolism and increase it's plasma level are Erythromycin Ciprofloxacin Cimetidine OCP Allopurinol", 'role': 'assistant'}]