When transporting elderly passengers, pregnant women, or passengers with mobility disabilities on an accessible commercial coach, what safety protocol must be followed?

1. Require disabled passengers to sit on the floor in the center aisle
2. Assist passengers during boarding, guide them to designated priority seats, secure wheelchairs with certified floor lock anchors and lap belts, and ensure comfort
3. Refuse carriage to all elderly passengers traveling without medical escorts
4. Store wheelchair users in the lower luggage compartment