Final answer:
The correct answer is option B. 90%.
Step-by-step explanation:
The question pertains to the Venturi tube, a device that utilizes the principle of fluid dynamics to create a pressure difference. According to Bernoulli's principle, when fluid flows through a constricted section of a tube, the velocity of the fluid increases, leading to a decrease in pressure. This is known as the Venturi effect. Downstream from the constriction, the tube widens, and the fluid's velocity decreases, allowing some of the pressure to be recovered.
The percentage of upstream pressure recovered downstream in a Venturi constriction is 90% (B), assuming there's no energy loss due to friction or turbulence, which is typically the case in an ideal scenario.