19. The equipment is consistence of a bowl which is rotated on its axis. When it is set in motion, the heaviest liquid and impurity are deposited nearest to the wall of the bowl, the water is separated to the wall, and the oil or the lighter liquid is separated into a layer close to the axis of the bowl. What equipment is above description? (A) Strainer (B) Purifier (C) Filter (D) Ejector