Final answer:
In order to drive a bus for 13 hours, a driver is required to have at least 8 hours off duty before beginning their shift, according to commercial driving regulations.
Step-by-step explanation:
In order to drive a bus for 13 hours, a driver must have had at least 8 hours off duty prior to this period. The regulations for commercial drivers typically mandate that drivers must have sufficient rest between driving shifts to ensure safety. The correct answer is b.8. This rest period allows for adequate sleep and recovery, helping to prevent driver fatigue and preserving road safety for both the driver and passengers.