What should the fef200-1200 be for a 50 year old male who is 6 feet 1 inch? a. 4.01/secb. 7.6 1/secc. 4.5 1/secd. 7.3 1/sec

I found one study online that test FEV 200-1200 in Lybian men. What they found is that FEV 200-1200 is negatively correlated with age and positively correlated with standing height. They indicate that FEV 200-1200 for this age group is 3.88, but the average height of their participants is a bit lower than 6 feet 1 in. 
Link to the study (http://thorax.bmj.com/content/thoraxjnl/43/11/923.full.pdf )
I found another study that test FEV in Indian their results are much higher than those in the previous study. Link to the study(https://pdfs.semanticscholar.org/4675/0b220f0ac39a78bd2aa0851f27496b0e288e.pdf).
I think the answer should be C.