Final answer:
The correct answer is B. 48 hours. This timeframe allows airlines to review necessary paperwork for travelers with service animals before the travel date.
Step-by-step explanation:
According to the Department of Transportation (DOT) regulations for travelers with service animals, all required paperwork regarding the animal's health, behavior, and training may need to be submitted 48 hours prior to the travel date. Airlines have the discretion to request these documents ahead of time or at the departure gate. For passengers with a service animal that is Seeing Eye-certified or has received other official training, providing the necessary documentation is typically straightforward.