Answer:
The following rules should Gertrude observe when placing items on top steel in the backroom:
Attach slot tags to the bin.
Do NOT have more than three different UPCs per pallet.
Shrink wrap, place on top steel, and bin regular pallet.
Therefore, the correct options are:
Attach slot tags to the bin.
Do NOT have more than three different UPCs per pallet.
Shrink wrap, place on top steel, and bin regular pallet.