After activating two fire extinguishing containers, which switch indicates that the system has been actuated?

When two fire extinguishing containers are activated, the switch that indicates the system has been actuated is the right system transfer switch labeled "TRANS." This switch is specifically designed to show that the transfer to the fire extinguishing system has occurred.

In many aircraft systems, fire extinguishing containers are activated through specific switches, and the right system transfer switch provides a clear visual or operational indicator that the fire suppression system is active and operational. This is critical for flight engineers and crew members, as it ensures that they are aware of the status of the fire suppression systems during flight operations and can take any necessary safety precautions.

The other options, while related to the fire suppression system or its operation, do not directly indicate the actuation of the extinguishing containers. Thus, the right system transfer switch "TRANS" is the correct choice for understanding the activation status of the fire extinguishing system in this context.