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
Following are true about COPD, except 
Select and explain. 
A. Reduced FEV1, B. Increased Residual Volume, C. Decreased Diffusion capacity (DLco), D. Decreased Maximal Expiratory Flow Rate (MEFR)
C: Decreased Diffusion capacity (DLco)
Answer: C: Decreased Diffusion capacity (DLco) 
Explanation: COPD is an obstructive lung disease. Obstructive diseases have reduced FEV1, FVC and reduced FEV1/FVC. Flow rates like MEFR (Maximal Expiratory Flow Rate ) are also reduced. 
Due to air-trapping, the residual volume is increased. 
Reduction in DLco is seen interstitial lung diseases or pneumonias, not in COPD . 
DLco may be reduced in Emphysema due to alveolar damage.