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': 'In upper air way obstruction all of the following changes are seen except : \nSelect and explain. \nA. Decreased Maximum breathing capacity, B. RV decreased, C. Decreased FEV, D. Decreased vital capacity', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. RV decreased', 'role': 'assistant'}]