A bus is offered 80 pounds of an allowed hazardous material class and 450 pounds of other allowed hazardous materials. Why should the driver refuse the combined load?

1. The total hazardous-material quantity exceeds the passenger-bus overall limit
2. The 80-pound package alone exceeds every passenger-bus limit
3. Passenger buses may never carry any hazardous material, even limited exceptions
4. The load is acceptable if placed under the floor