In subcritical flow in a channel, ∆z m is the minimum height of a smooth hump that can be installed to cause critical flow over the hump. If the hump of height ∆z > ∆z m is installed, then the flow...

In subcritical flow in a channel, ∆z_m
is the minimum height of a smooth hump that can be installed to cause critical flow over the hump. If the hump of height ∆z > ∆z_m
is installed, then the flow over the hump will be

(a) subcritical

 (b) supercritical

(c) critical and the upstream water surface will rise

(d) critical and a lowering of the upstream water surface will occur