To avoid vaporisation in the pipe line, the pipe line over the ridge is laid such that it is not more
than
(A) 2.4 m above the hydraulic gradient
(B) 6.4 m above the hydraulic gradient
(C) 10.0 m above the hydraulic gradient
(D) 5.0 above the hydraulic gradient
than
(A) 2.4 m above the hydraulic gradient
(B) 6.4 m above the hydraulic gradient
(C) 10.0 m above the hydraulic gradient
(D) 5.0 above the hydraulic gradient