Which endorsement is not necessary for a school bus driver?

The C endorsement is not necessary for a school bus driver, as it is typically associated with driving standard vehicles that do not require a commercial driver's license (CDL). In the context of driving a school bus, the P endorsement (Passenger) and the S endorsement (School Bus) are specifically required to ensure that the driver is qualified to transport students safely. These endorsements indicate that the driver has received additional training and has passed the necessary tests to operate a vehicle designed for transporting multiple passengers, particularly children.

The B endorsement is related to driving larger commercial vehicles and may be necessary depending on the specific vehicle being operated; however, it is not specific to the requirements for a school bus driver. Thus, since the C endorsement does not pertain to the unique responsibilities and requirements of operating a school bus, it is the correct choice as the endorsement not necessary for a school bus driver.