Which statement best describes the role of a shell program?

The role of a shell program primarily revolves around interpreting and executing user commands. A shell acts as an interface between the user and the operating system. When a user types a command in the shell, it processes that input by parsing the command, managing any parameters, and then executing the appropriate program or instruction. This enables users to interact with the operating system and perform various tasks like file manipulation, program control, and script execution.

In contrast to the other options, managing hardware resources pertains more to the kernel of the operating system rather than a shell. A graphical user interface simplifies interaction with the computer through visuals and icons, which is distinct from the command-line nature of a shell. Scheduling tasks is a function typically handled by the operating system's task scheduler, which allocates CPU time and manages processes, rather than the shell itself. Thus, the correct answer captures the fundamental function of a shell program effectively.