If fluid is flowing through the hole in an orifice plate, what does the restricted fluid movement cause?

The correct choice is the difference in pressure because when fluid flows through an orifice plate, the constriction creates a change in velocity and pressure in the fluid stream. According to Bernoulli's principle, as the fluid passes through the restricted area of the orifice, the velocity of the fluid increases, and consequently, the pressure decreases. This pressure drop across the orifice is a critical measure that can be used in various applications, such as flow rate calculations, pressure monitoring, and control processes.

The other choices do not accurately describe the primary effect caused by the restriction of fluid movement in this context. While a slower flow may occur downstream, the fundamental principle at work is the change in pressure, which is essential for analysis in fluid mechanics and instrumentation. An alternate flow for the control panel does not directly relate to the immediate consequence of fluid moving through an orifice plate, and while stress on the instrument could occur under certain conditions, it is not the primary mechanism observed when fluid navigates through an orifice.