Final answer:
The true statement about the Class 3 operator's license is that holders can operate a truck with air brakes, although additional endorsements may be required for certain vehicles or materials.
Step-by-step explanation:
The correct statement about the holder of a Class 3 operator's license is that they can operate a truck with air brakes. The Class 3 license typically allows drivers to operate a range of commercial vehicles, including small and large trucks, some of which may be equipped with air brake systems. However, additional endorsements may be required to operate vehicles with air brakes or to transport hazardous materials. Restrictions about the number of axles a vehicle may have or whether hazardous materials can be carried depend on the specific endorsements on the license and the regulations in the jurisdiction where the license is issued.