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: Medicine
[{'content': 'Bronchial asthma can be diagnosed by-a) Wheezeb) Dyspneac) Normal FEV1d) Coughe) Reversible obstruction \nSelect and explain. \nA. a, B. b, C. ae, D. ad', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]