A Washington school bus has air brakes. Which license-related statement is correct for a driver operating it?

1. The driver may keep an air brake restriction as long as the bus carries students
2. The driver must have the proper CDL class, Passenger and School Bus endorsements, and the air brake restriction removed for an air-brake bus
3. The School Bus endorsement removes all air-brake testing requirements
4. Air brakes are allowed only on non-school buses