This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chronic Obstructive Pulmonary Disease, Subject name: Medicine
In COPD w hich is true - 
Select and explain. 
A. FEV1/FVC<0.7, B. FEVl/FVC|, C. RV|, D. TLV |
A: FEV1/FVC<0.7
Answer: A: FEV1/FVC<0.7 
Explanation: Ans. is 'a' i.e., FEV1 / FVC < 0.7 The lung function tests in obstructive lung disease can be summarized as -o Forced expiratory vital capacity (FEVc)- Normal to slightly decreasedo Forced expiratory volume in 1 secQ (FEV )-Decrease out of proportion to FVCo FEV1/FEV1Q-Decrease can be as low as 20% - 30%o Peak expiratory flow rate-Decreasedo Total lung capacity-Increaseo Residual volume-Increaseso Functional residual capacity-Higher