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': 'Advantage of salmeterol over salbutamol is its : \nSelect and explain. \nA. Shorter duration of action, B. More potency, C. Longer duration of action, D. Lesser cardiac effects', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]