This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Flow Volume curve, Spirometry and DLCO, Subject name: Medicine
If FEV1 is 1.3 L, FVC is 3.1 L in an adult man, the pattern is suggestive of: 
Select and explain. 
A. Normal lung function, B. Restrictive lung disease, C. Obstructive lung disease, D. None of the above
C: Obstructive lung disease
Answer: C: Obstructive lung disease 
Explanation: Obstructive lung disease:- - FEV1 is reduced due to obstruction of air escaping from the lungs. Thus, FEV1/ FVC ratio will be reduced. Restrictive lung disease:- - FEV1 and FVC are equally reduced due to fibrosis or other lung pathology . Thus,FEV1/FVC ratio -normal or even increased. In this question, a ratio of 1.3/3.1 is about 40% in contrast to a normal of > 80%.