Which of the following tasks is performed by an operating system?

An operating system is fundamentally responsible for managing computer hardware and software resources, and one of its key functions is memory management. This includes overseeing the allocation and deallocation of memory space as needed by various applications and the system itself, ensuring that each program has sufficient memory to execute while maintaining system stability.

Memory management involves tracking each byte in a computer's memory and managing the exchange of data between the RAM and storage drives. The operating system uses various techniques to optimize memory use, such as paging and segmentation. Effective memory management helps to prevent memory leaks and ensures that applications run efficiently without crashing or slowing down due to insufficient memory resources.

The other tasks listed, like writing application software, designing user interfaces, and creating network protocols, are typically functions carried out by developers, UI/UX designers, or network engineers and do not fall under the core responsibilities of an operating system. Instead, the OS provides a platform that supports applications, manages user interfaces, and facilitates network communications, but it does not create these components itself. Thus, memory management is distinctly recognized as a primary task of an operating system.