What should a passenger do if they are traveling with a service animal?

When traveling with a service animal, it is essential for the passenger to notify the crew upon boarding. This step is important because it allows the crew members to be aware of the situation, ensuring that they can provide appropriate assistance and accommodations for the passenger's needs. Additionally, informing the crew helps maintain a safe and comfortable environment for all passengers on board.

Service animals are trained specifically to assist individuals with disabilities, and their presence is typically recognized by transport regulations. Notifying the crew helps ensure that the service animal complies with any necessary policies and that the crew understands how to help facilitate a positive experience for the passenger.

The other choices do not align with the policies regarding service animals. For instance, keeping the animal in a carrier or requiring a muzzle may not be relevant, as service animals are usually trained to behave appropriately in public settings and do not need to be confined in a carrier during travel. Moreover, choosing not to bring the animal at all would dismiss the benefits that the service animal provides to its handler. Thus, notifying the crew is the most appropriate and responsible action for a passenger traveling with a service animal.