Checking the door locking function: Question

Which door has the problem?

1. Driver door.

   Refer to Checking the driver door 

2. Passenger door.

   Refer to Checking the passenger door 

3. Rear left door.

   Refer to Checking the rear left door 

4. Rear right door.

   Refer to Checking the rear right door 

Choose the correct option from above.