A shipper asks to load 120 pounds of one allowed hazardous-material class and 300 pounds of other allowed classes on a bus. Which issue makes the load unacceptable?

1. More than 100 pounds of one class is not allowed on the bus
2. The total is over 500 pounds
3. Any allowed hazardous material must ride in the passenger aisle
4. Only the driver may decide to ignore class limits