A sewer is laid from a manhole to a manhole , 250 m away along a gradient of 1 in 125. If the
reduced level of the invert at is 205.75 m and the height of the boning rod is 3 m, the reduced
level of the sight rail at , is
(A) 208.75 m
(B) 202.75 m
(C) 206.75 m
(D) 211.75 m