Before departing from a bus stop after passenger boarding and alighting, what must the driver verify regarding the passenger doors?

1. Start accelerating immediately while the doors are pneumatically closing to save time
2. Rely solely on passengers to shout if their limbs are caught in the door
3. Verify via the interior mirror and door indicator lights that all passenger doors are fully closed and no passenger clothing or bags are trapped, before starting to move (车门未关好，严禁起步)
4. Keep the front door open for fresh air circulation while driving