What is the correct visual mirror scanning routine a bus driver must perform when preparing to pull away from a curb-side bus stop?

1. Look only at the left side mirror and accelerate aggressively into the main traffic stream
2. Sound the horn loudly and pull out without checking the right side mirror
3. Look only at the speedometer while pulling away
4. Check the interior passenger cabin mirror, check the right exterior mirror for trailing pedestrians/bicycles, check the left exterior mirror for passing traffic, activate the left turn signal, and pull out smoothly