Which of the following federal law enforcement agencies is responsible for enforcing federal criminal laws?

The Federal Bureau of Investigation (FBI) is the correct answer because it is the principal federal agency tasked with enforcing federal criminal laws across various jurisdictions. The FBI handles a wide range of criminal activities, including but not limited to terrorism, cybercrime, organized crime, and white-collar crime. It operates under the jurisdiction of the Department of Justice and plays a critical role in upholding the rule of law and protecting national security.

Each of the other agencies has specific responsibilities that, while they may include aspects of law enforcement, do not encompass the broad enforcement of federal criminal laws in the same way the FBI does. The Secret Service primarily protects the President and other high-level officials, and also investigates financial crimes such as counterfeiting. The Bureau of Alcohol, Tobacco, Firearms and Explosives focuses specifically on laws related to alcohol, tobacco, firearms, and explosives. Meanwhile, the U.S. Marshals Service is known for managing and transporting federal prisoners and executing federal court orders but is not primarily focused on the broad enforcement of federal criminal laws like the FBI.