A Valve Is Closed and the Fluid Within a Pipe

Multiple Choice

A valve is closed and the fluid within a pipe is stationary. When the valve is opened, fluid flows through the pipe. What happens to the pressure in the pipe when the valve is opened?

A) The direction of the pressure change depends on the direction of the fluid flow.
B) The direction of the pressure change depends on the density of the fluid.
C) The pressure decreases.
D) The pressure increases.
E) The pressure remains the same.