This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System, Subject name: Physiology
In upper airway obstruction all of the following changes are seen except 
Select and explain. 
A. Decreased maximum breathing capacity, B. RV decreased, C. Decreased FEV, D. Decreased Vital capacity
B: RV decreased
Answer: B: RV decreased 
Explanation: Ans. (b) RV decreased(Ref: Ganong, 25th ed/p.628)Increase in residual volume denotes "air trapping" which is classically seen in obstructive lung diseases