What is the main function of the kernel in an operating system?

The kernel is the core component of an operating system that has several crucial responsibilities, one of which is the management of processes. It operates at a low level, directly interacting with the computer's hardware and managing the execution of processes, which includes their creation, scheduling, and termination.

By overseeing these processes, the kernel ensures that they are allocated CPU time effectively and can run concurrently without interfering with each other. Process management involves not just starting and stopping processes but also handling communication between them and maintaining their states, which is essential for multitasking environments.

Other options presented do have validity within an operating system but describe functions that occur at higher levels or are specific tasks that the kernel supports. The display of graphical interfaces is primarily handled by additional software layers (such as graphical user interfaces) rather than the kernel itself. Input and output operations are also critical functions, but they are a part of broader system I/O management, which the kernel facilitates rather than solely controls. Time slicing is a scheduling technique used by the kernel but is just one aspect of its more extensive process management role.