Which agency is responsible for regulating commercial driver's licenses?

Answer: B — Federal Motor Carrier Safety Administration (FMCSA)

The Federal Motor Carrier Safety Administration (FMCSA) is the agency responsible for regulating commercial driver's licenses. This agency falls under the Department of Transportation and specifically focuses on the safety of commercial motor vehicles and drivers. The FMCSA establishes requirements for obtaining a Commercial Driver's License (CDL), ensuring that drivers meet specific standards for safety, training, and health. The FMCSA also governs the regulations that affect interstate and intrastate commercial driving, including vehicle standards and driver qualifications. This includes the implementation of the Entry-Level Driver Training (ELDT) requirements, which are designed to ensure that new commercial drivers receive adequate training before they are allowed to operate large vehicles. Other agencies mentioned, such as the DOT, provide a broader regulatory framework for transportation as a whole, rather than specifically focusing on commercial driver's licensing. The National Highway Traffic Safety Administration (NHTSA) deals primarily with vehicle safety standards and traffic regulations, while the Occupational Safety and Health Administration (OSHA) focuses on workplace safety, which does not encompass the specific regulations regarding commercial drivers.