This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'All of the following statements regarding theophylline are true, except: \nSelect and explain. \nA. Increases cAMP, B. Inhibits phosphodiesterase, C. Increase in dose is required in smokers, D. Increase in dose is required in cardiopulmonary disease', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Theophylline is a methylxanthine, used in the treatment of bronchial asthma. Its dose has to be reduced in elderly (age > 60 years), in congestive hea failure, pneumonia and liver failure.', 'role': 'assistant'}]