Final answer:
A federally regulated driver on a 7-day cycle must take 36 hours off-duty to end the cycle and begin a new one to ensure safe driving conditions.
Step-by-step explanation:
A federally regulated driver who is on a 7-day cycle must take 36 hours off-duty to end the cycle and begin a new cycle. The correct answer is: b) 36 hours. This rest period is designed to ensure that drivers have adequate rest and are not overworked, which could lead to dangerous situations on the road. A federally regulated driver on a 7-day cycle must take 36 hours off-duty to end the cycle and begin a new one to ensure safe driving conditions.