The total length of a runway is 1000 m. The elevation at distance 0,200 m, 400 m, 600 m, 800 m and 1000 m are 100.0 m, 99.2 m, 101.0 m, 101.8 m, 101.4 m and 101.0 m respectively. The effective gradient of runway will be______________?
A. 0.10%
B. 0.26%
C. 0.43 %
D. 0.65%