Under what condition is a transport unit carrying Class 7 goods considered to be operating under 'Exclusive Use'?

1. When the vehicle carries 5 different customers' parcels at the same time
2. When the vehicle is owned by a public bus company
3. When a single consignor has sole use of the vehicle and all loading/unloading operations are performed in accordance with the consignor's or consignee's instructions
4. When the driver operates without wearing a seatbelt