What kind of license must drivers of heavy trucks possess?

Answer: B — Commercial or chauffer's license

Drivers of heavy trucks must possess a commercial or chauffeur's license because these vehicles often exceed the weight limits and require specialized skills to operate safely. A commercial driver's license (CDL) is specifically designed to ensure that drivers have the necessary training and knowledge regarding the operation of large vehicles, including understanding regulations, safety procedures, and handling various driving conditions. The other types of licenses do not adequately prepare an individual for the complexities involved in driving heavy trucks. A standard driver's license typically covers only regular passenger vehicles and does not include the training necessary for navigating larger vehicles. A restricted license can impose limitations that wouldn't meet the requirements for operating heavy trucks. Similarly, a CDL learner's permit is more of a preliminary step that allows a person to practice driving under specified conditions before they obtain a full commercial license.