What action is taken under FPCON Delta?

FPCON Delta is the highest level of security alert, indicating that there is an imminent threat of terrorist activity or a similar security risk. When FPCON Delta is implemented, all available resources are mobilized to respond to the immediate threat, which can include heightened surveillance, increased personnel presence, and enhanced security measures at specific locations. This action is critical for preventing potential attacks and ensuring the safety of all personnel and assets.

In this context, the focus is on deploying responses that directly address the danger posed by the imminent threat, marking a proactive approach to security rather than merely reacting to incidents that have already occurred. Other options suggest varying degrees of response but do not capture the urgency and intensity of action required during FPCON Delta. Therefore, the correct understanding of FPCON Delta involves recognizing the immediate and serious nature of threats that demand significant and prompt security actions.