The depth of the center of pressure on a vertical rectangular gate 8 m wide and 6 m high, when the water surface coincides with the top of the gate, is ______________________?

A. supersonics, as with projectile and jet propulsion
B. full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
C. simultaneous motion through two fluids where there is a surface of dis-continuity, gravity forces, and wave making effect, as with ship’s hulls
D. all of the above
E. none of the above

A. atmospheric pressure
B. surface tension
C. force of adhesion
D. force of cohesion
E. viscosity