What method represents one component with several symbols in various locations on a ladder diagram?

The correct answer is detached symbology. This method allows for representing one component with multiple symbols spread out across different locations on a ladder diagram. Detached symbology is particularly useful in complex diagrams where clarity and organization are essential. It enables the designer to draw individual elements separately and wherever they fit best in the schematic, rather than being constrained to a single placement. This approach not only enhances readability but also helps in understanding the operational relationships between different components by visually separating them while maintaining a cohesive relationship in function.

The other methods, while they may involve symbols, do not specifically encapsulate the idea of using several symbols for one component in varying locations. For example, parallel representation typically refers to components being shown in parallel paths, combined symbology usually indicates multiple components being grouped together to represent them collectively, and layered symbols often involve stacking or arranging symbols in a way that depicts additional detail or depth rather than dispersing them across the diagram.