A system is subdivided into which of the following levels?

The correct choice reflects a hierarchical structure commonly used in system engineering and design. The terms "Set, Group, Unit, Assembly, subassembly, parts" represent a systematic approach to organizing and defining the various elements within a complex system.

In this context, a set encompasses the entire system, while a group might represent a collection of similar units or assemblies with a common function. Units are individual entities that contribute to the overall operation of the system. An assembly is a collection of parts or subassemblies, and a subassembly is a smaller component made up of several parts that alone serve a specific function within the larger assembly. Each level serves to break down the system into manageable sections, allowing for easier management, analysis, and troubleshooting.

Understanding this hierarchical approach is essential for any electronics technician as it aids in system design, diagnostics, and maintenance. It illustrates how individual components contribute to the overall functionality of the system, which is critical in troubleshooting and repair processes.