Right option is (b) ultrafiltration
To elaborate: Ultrafiltration is a type of crossflow microfiltration which is done by pressurizing the solution flow, which is tangential to the surface of the supported membrane. In industries such as pharmaceutical, chemical, food and beverage processing and waste water treatment, ultrafiltration is employed in order to recycle flow or add value to later products. Filtration is a technique for separation of molecules based on its size. Plate and frame press is a machinery used for filtration. Chromatography a step in purification.