Which of the following indicates a circuit that is controlled by a switch?

A circuit that is controlled by a switch is typically represented by a solid line accompanied by specific symbols that denote the switch within a schematic diagram. In electrical schematics, a solid line indicates a continuous path for current flow, and the presence of a symbol in conjunction with this line clearly illustrates the point at which the circuit can be opened or closed by the switch. This representation enables anyone studying the blueprint to understand how the switch interacts within the circuit, highlighting its function in controlling the flow of electricity.

The other choices feature representations that do not convey the operation of a switch effectively. Dotted and dashed lines are often used to indicate different types of connections or pathways that may not involve direct electrical continuity or can signify non-functional elements of a circuit. A zigzag line usually indicates a resistor or the specific style of a component but does not represent a switch. Therefore, the solid line with a symbol is the accurate representation of a switch-controlled circuit.