Which agency is the lead for incidents related to terrorism occurring within the United States?

The correct choice is the Federal Bureau of Investigation (FBI), as it serves as the lead agency for managing terrorism incidents within the United States. The FBI is responsible for investigating and preventing terrorist threats, as well as responding to acts of terrorism. It operates under the premise of protecting both the country and its citizens by addressing domestic terrorism concerns and collaborations with various state and local law enforcement agencies.

The Department of Justice plays a critical role in prosecuting terrorism-related offenses but does not handle the immediate response and incident management. The Department of Homeland Security focuses on overall national security and emergency preparedness but acts in a support capacity during terrorism incidents. The Central Intelligence Agency primarily deals with national security threats outside of the U.S. and is not tasked with domestic terrorism response.