What is the primary objective of terrorists targeting U.S. citizens?

The primary objective of terrorists targeting U.S. citizens encompasses a variety of tactics aimed at achieving multiple goals, which include maximum casualty, mass destruction, and public fear. Terrorist organizations often seek to inflict the highest number of casualties to create shock and compel attention to their cause; this leads to widespread fear among the public, which can destabilize communities and governments.

In addition to causing physical harm, the psychological impact of their actions is vital for terrorists. By instilling fear, they can manipulate public perception and possibly sway government policies or actions that align with their objectives. The goal is not just to damage property or take lives, but to provoke a reaction that can change societal or governmental behavior.

When considering all these factors, it's evident that terrorists aim for a comprehensive strategy that encompasses casualty, destruction, and instilling fear, making "all of the above" the most accurate representation of their primary objectives.