ANS:B - wet classifier

A hydrocyclone is a wet classifier. A hydrocyclone is a device used for the classification, separation, and concentration of solids in a liquid suspension based on their density, size, or other physical properties. It operates by creating a swirling flow pattern within a cylindrical or conical chamber, which causes particles of different densities or sizes to separate and accumulate in different zones within the chamber. In industrial applications, hydrocyclones are commonly used in mineral processing, wastewater treatment, and other processes where solid-liquid separation is required. They are particularly effective for separating fine particles from a liquid suspension and can be used for both classification and concentration purposes. Therefore, a hydrocyclone is best described as a wet classifier.