Civil gate questions

The downstream end of long prismatic channel of mild slope ends in a pool created by a dam. The resulting non- uniform water surface profile can be described as one of the following------------------
(a) M3 profile ending in a hydraulic pump
(b) M1 profile that les above normal depth line
(c) M2 profile that lies between critical and normal depth lines
(d)M3 profile that lies between critical and normal depth lines