The detention time of a circular tank of diameter d and water depth H, for receiving the sewage Q per hour, is________________?

A. the direction and magnitude of the velocity at all points are identical
B. the velocity of successive fluid par-ticles, at any point, is the same at suc-cessive periods of time
C. the magnitude aricf direction of the velocity do not change from point to point in the fluid
D. the fluid particles move in plane or parallel planes and the streamline pat-terns are identical in each plane
E. velocity, depth, pressure, etc. change from point to point in the fluid flow

A. wake
B. drag
C. lift
D. boundary layer
E. aerofoil section

A. adhesion
B. cohesion
C. viscosity
D. compressibility
E. surface tension