The correct answer is (a) crossflow microfiltration
For explanation I would say: To avoid the problems of buildup of filter cake, the crossflow microfiltration was developed. This process allows high tangential flow of feedstock across the surface of the filter. Filtration is a separation technique which separates based on the particle size. Ultrafiltration is a type of crossflow microfiltration technology. Rotary vacuum filter is used for continuous filtration.