Which one of the following statements is correct?
(a) Hydraulic grade line and energy grade line are the same in fluid flow problems.
(b) Energy grade line lies above the hydraulic grade line and is always parallel to it.
(c) Energy grade line lies above the hydraulic grade line and they are separated from each other by a vertical distance equal to the velocity head.
(d) The hydraulic grade line slopes upwards meeting the energy grade line only at the exit of flow.