What types of animals are allowed on federal property?

Service animals are specifically trained to assist individuals with disabilities, and under federal law, particularly the Americans with Disabilities Act (ADA), they are the only type of animals granted access to federal property. This definition ensures that these animals are trained to perform tasks directly related to the person's disability, providing necessary support in various environments, including federal buildings.

The other options do not align with the regulations surrounding animal access on federal property. For instance, while documentation may be required for certain animals, it does not grant access rights under federal law in the ways that service animals do. Similarly, although leashing pets is standard practice in many areas, it doesn’t address the strict guidelines regarding public access. Finally, the total prohibition of all animals would not account for the legal requirements to allow service animals, making option B the only correct choice.