In the accompanying figure, the two-position, two-circuit selector switch allows only one control circuit rung to be _______________ at a time, so simultaneous operation is not possible.

Two-Position

A type of control or device that has two distinct settings or positions, such as "on/off" or "open/closed."

Selector Switch

A switch that allows the user to select among multiple positions or modes, often found on control panels for machinery.

Control Circuit Rung

A section or level within a control circuit diagram, often represented as horizontal lines that show the flow of electrical control signals.