Which of the following best describes an operating system?

The best description of an operating system is that it is the system software that manages hardware and software resources. An operating system serves as an intermediary between users and the computer hardware. Its primary functions include managing the computer's hardware components such as the CPU, memory, and storage devices, while also providing services for application software. This enabling environment allows users to run programs, manage files, and interact with the system effectively.

In contrast, application software refers to programs designed to perform specific tasks for users, such as word processing or spreadsheet applications, and is not responsible for managing the overall system. A programming language is a formal set of instructions that can be used to create software applications but is not itself an operating system. Lastly, hardware components refer to the physical parts of a computer system, such as the keyboard, monitor, and internal circuits, which work in conjunction with the operating system but do not encompass its functions. Thus, option B clearly captures the essential role and definition of an operating system.