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: Physiology
[{'content': 'Increased airway resistance is/are caused by \nSelect and explain. \nA. Forced expiration, B. Dense air, C. Low lung volume, D. All', 'role': 'user'}, {'content': 'Answer: D \nExplanation: A, B, C i.e. Forced expiration, Dense air, Low lung volume', 'role': 'assistant'}]