Which best describes a characteristic of an operating system (OS)?

An operating system (OS) serves as a crucial intermediary between the computer's hardware and the user applications, facilitating communication and resource management. This role is essential because the OS manages hardware resources such as the CPU, memory, storage, and input/output devices, allowing user applications to operate without needing to directly interface with the hardware. This abstraction enables developers to create applications that can run on various hardware configurations without needing specialized code for each type of hardware.

By providing services such as process management, memory management, and device management, the OS ensures that applications can run efficiently and concurrently, handling tasks like scheduling and prioritizing processes. This characteristic highlights the OS’s vital function in maintaining system stability, performance, and usability for both the hardware and the applications that run on it.

In contrast, the other options present inaccurate representations of an OS's characteristics, emphasizing its pivotal role in computer systems.