A false alarm may trigger an investigation of the system, which is determined by _______.

The correct choice, which is the control center, highlights the central role that monitoring and communication facilities play in the management of pipeline corrosion control systems. The control center is responsible for overseeing the operation and monitoring of the system's integrity. When an alarm—true or false—is triggered, it's the control center that assesses the situation and determines the necessity of an investigation.

The control center typically has access to real-time data and can analyze trends, patterns, and discrepancies in the system. This capability allows it to differentiate between a genuine alarm and a false one based on comprehensive information and system diagnostics. Thus, it acts as the central decision-making point for whether further investigation is needed, ensuring that resources are appropriately allocated and potential issues addressed efficiently.

The other options, while they may play roles in the overall management of the pipeline, do not have the same level of authority or comprehensive situational awareness required to make this specific determination about false alarms. Field personnel and the job site supervisor may respond to alarms or assist in the investigation, but they primarily operate based on directives from the control center. SCADA (Supervisory Control and Data Acquisition) systems provide the data and alarm signals but rely on the control center's interpretation and action regarding those alarms.