What document must a driver have while operating a motor vehicle at the airport?

Answer: B — valid driver's license

To operate a motor vehicle at the airport, it is essential for a driver to have a valid driver's license. This document serves as proof that the driver has undergone the necessary testing and has the legal right to operate a vehicle. It ensures that the driver is knowledgeable about traffic laws, safe driving practices, and the necessary regulations specific to driving in airport areas. While having vehicle registration, insurance paperwork, and a parking permit may be necessary for other operational aspects or compliance with local regulations, the foundational requirement for legally guiding a vehicle is a valid driver's license. This is why it is critical that drivers carry this document when driving in an airport environment.