Which of the following can be classified as a service animal?

A service animal is specifically defined under the Americans with Disabilities Act (ADA) as a dog that has been individually trained to perform tasks for a person with a disability. This includes tasks like guiding individuals who are visually impaired, alerting those who are deaf, or providing support during a medical crisis.

While other animals, such as cats, rabbits, and birds, may provide emotional support or companionship, they do not qualify as service animals under the ADA unless they are trained to perform specific tasks related to a person's disability. This clear distinction highlights why dogs are the only recognized category of service animals in this legal framework. Therefore, dogs meet the criteria set forth by the ADA to help individuals with various disabilities, making them the correct answer in this context.