A ---- provides maximum accuracy when detecting flow in fluids that contain larger amounts of suspended solids such as slurries

The venturi tube is designed to measure fluid flow with a high degree of accuracy, particularly in situations where the fluid contains suspended solids, such as slurries. This is due to its specific geometric shape, which narrows at a central section and creates a pressure difference that can be correlated to flow rate.

In environments with larger amounts of suspended solids, it’s crucial to have a flow measurement device that minimizes the risk of clogging, which is a common issue with other types of flow measurement technologies. The venturi's construction helps ensure that solids can pass through the meter without getting trapped, thus providing consistent and accurate readings.

While orifice plates and standard flow meters can also be used for flow measurement, they may struggle with slurries, as they can become obstructed or provide less reliable data due to the variable density and viscosity of the mixture. The option of conduit does not refer specifically to a method of flow measurement, making it unsuitable for the context of the question. Therefore, the venturi tube stands out as the best choice for detecting flow in such challenging conditions.