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': 'Cough of more than 3 months duration in a non-smoker with normal chest X-ray. All reasons are true EXCEPT: March 2013 (e) \nSelect and explain. \nA. Post nasal drip, B. Asthma, C. Gastroesophgeal reflux, D. Common cold', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D i.e. Common cold', 'role': 'assistant'}]