What label is used for supplementary circuits?

The label used for supplementary circuits is identified as X1J. This labeling convention is part of standard practices within electrical and electronic systems to categorize and specify the functions of different types of circuits and connections.

In this context, supplementary circuits refer to additional circuits that support or complement the main circuit in a system, allowing for enhanced functionality or additional features. Using specific labeling such as X1J helps technicians and engineers quickly identify these circuits when troubleshooting or performing maintenance.

The other options, while they may represent different types of circuits or components, do not specifically denote supplementary circuits. Familiarity with such labeling helps ensure clarity and efficiency in systems management and repair.