What is the primary function of system restore in Windows?

The primary function of System Restore in Windows is to revert the system to a previous state to recover from issues. This tool allows users to roll back their operating system files, settings, and installed programs to a point in time before a problem occurred, such as after a software installation or a system update that may have caused instability. By restoring the system to an earlier configuration, users can resolve issues without affecting their personal files, such as documents, photos, or videos.

System Restore is particularly useful in troubleshooting and recovering from problems that can arise from software conflicts, corrupted drivers, or changes made to system settings. It creates restore points automatically during system events like software installations or system updates, giving the option to return to a known stable state.

The other options do not accurately describe the function of System Restore. While system maintenance activities such as file deletion, drive optimization, or application upgrades are important, they are not the primary purpose of System Restore. The focus of this feature is specifically on recovery and restoration, making option B the correct choice.