Which of the following is responsible for screening individuals potentially connected to terrorism?

The Terrorist Screening Operation Unit is specifically tasked with identifying and screening individuals who may have connections to terrorism. This unit is part of the broader U.S. counterterrorism strategy and plays a crucial role in the vetting process, ensuring that individuals who pose a potential threat to national security can be identified early on. By maintaining a comprehensive watch list, the unit aids various federal agencies in their efforts to prevent terrorism and protect public safety.

In comparison, while the Terrorist Threat Integration Center serves an important function in integrating intelligence related to terrorism and providing assessments, its primary role is not the direct screening of individuals. The Top Secret - Sensitive Compartmented Information designates a classification level of sensitive information rather than a screening authority. The Universal Index is more of a database reference for intelligence and law enforcement rather than a focused unit for screening individuals linked to terrorism. Thus, the specialization and direct mandate of the Terrorist Screening Operation Unit make it the correct answer for this question.