Final answer:
Bus and emergency vehicle drivers are exempt from wearing seatbelts due to other safety features in their vehicles that are designed to protect occupants.
Step-by-step explanation:
In this question, the drivers who are exempt from wearing seatbelts are bus and emergency vehicle drivers (option b). These drivers are exempt because their vehicles are equipped with other safety features such as roll cages and secure seating systems that are designed to protect occupants in the event of an accident. It is important to note that while these drivers are exempt from wearing seatbelts, they still have a responsibility to ensure the safety of their passengers by following all traffic laws and driving safely.