What must drivers of heavy trucks carry with them or have on the truck?

Answer: B — Driver's license and registration papers

Drivers of heavy trucks must carry their driver's license and registration papers as a fundamental requirement. The driver's license is essential as it proves that the driver has the necessary qualifications and legal permission to operate the heavy vehicle. Additionally, registration papers are crucial for verifying that the vehicle is properly registered with the state, ensuring it meets legal standards for operation on public roads. While proof of insurance, a vehicle inspection certificate, and a medical certificate are also important documents for drivers of heavy trucks, they may not be universally required to be carried at all times, depending on local regulations. However, having the driver's license and registration papers is a baseline expectation for legal operations and helps authorities verify compliance with transportation laws.