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': 'Therapeutic blood range of theophylline in microgram per L is: \nSelect and explain. \nA. 0-5, B. 10-May, C. 15-May, D. 20-May', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Theophylline is having a narrow margin of safety so therapeutic drug monitoring is essential If levels increase more than 20mg/L- side effects occurs ESSENTIAL OF MEDICAL PHARMACOLOGY SEVENTH EDITION KD TRIPATHI PGNO.226', 'role': 'assistant'}]