Which component must provide shock hazard control for firefighters during a rapid shutdown?

The correct choice focuses on the rapid shutdown function, which is crucial for ensuring safety during emergency situations involving solar photovoltaic systems. This function is specifically designed to mitigate shock hazards for firefighters and other emergency responders.

When activated, the rapid shutdown function de-energizes the solar array, significantly lowering the voltage present in the system. This reduction in voltage minimizes the risk of electric shock when firefighters engage with the system during fire suppression efforts or other emergencies. The National Electrical Code (NEC) has specific requirements outlined in Article 690 that mandate this function to enhance safety, particularly in circumstances where there is a potential for rescuing individuals or preventing further hazards.

In contrast, while the service disconnect, the building's electrical system, and the inverter have roles in the overall electrical safety and system operation, they do not specifically address the immediate shock hazard concerns for firefighters during emergency responses in the same way that the rapid shutdown function does. The service disconnect, for instance, may isolate the entire system but does not inherently ensure that the solar array or its components are de-energized instantaneously for safety.