A California applicant wants to operate a passenger bus equipped with air brakes. Which knowledge-test path is correct?

1. Pass the passenger-required knowledge from Sections 2 and 4 and also pass Section 5 for air brakes
2. Pass only Section 4 because passenger rules include air brakes
3. Pass only Section 5 because air brakes are more important than passenger safety
4. Skip knowledge testing and rely on the passenger skills test