What step should be taken after ensuring the door safety straps are stowed?

After ensuring the door safety straps are stowed, closing and arming the door is the next crucial step in the boarding or pre-flight process. This action is essential for ensuring the safety of the aircraft by preparing the door for flight. When the door is closed and armed, it indicates that the door will not be able to be opened during flight and is secured, minimizing the risk of any in-flight emergencies related to door integrity.

This step is critical because it sets up the aircraft for a safe departure. Closing and arming the door also signals to the rest of the crew and potentially the ground staff that the cabin is secure and that the aircraft is ready for its next phase of operation, whether that be taxiing or final safety checks.

The other options, while important in different contexts, do not follow immediately after securing the door straps. Notifying passengers of the delay, checking all other doors, and informing ground staff are tasks that may be necessary at various points in the boarding process or flight preparations but are not the immediate next step after stowing the safety straps.