Which system is characterized as the Army's strategic, theater, and tactical command, control, and communications system?

The correct choice identifies GCCS-A, which stands for Global Command and Control System-Army. This system is designed to provide comprehensive command, control, and communications capabilities across various operational levels, including strategic, theater, and tactical environments. GCCS-A integrates information from multiple sources and enables commanders to make informed decisions by providing real-time situational awareness and facilitating communication across the military hierarchy.

This system's significance lies in its ability to enable coordinated actions among military units and enhance operational effectiveness through improved information sharing and decision-making processes. By leveraging modern technology and data management practices, GCCS-A supports joint and combined operations, allowing for seamless interaction between different command levels and branches of the military.

In contrast, the other options refer to specific systems or capabilities that do not encompass the broad scope of command, control, and communications for strategic, theater, and tactical operations as GCCS-A does.