Pick out the correct statement.

• It is preferred to use a vertical condenser for condensation of vapor from a distillation column without sub-cooling
• Draining of residual liquid on tray during shut down of distillation column is facilitated by weep holes.
• Random packing a packed tower offers the advantage of lower pressure drop and higher throughput of fluids as compared to regular/stacked packing.
• Risers are generally not connected to the plate in a distillation coloumn by bolts, rivets or welding.