The correct answer is D. Doskey.
A system tool is a program that is used to manage the computer's system resources. Some common system tools include Scandisk, Drive Space, and Disk Defragmenter.
Scandisk is a program that checks the integrity of a disk drive and repairs any errors that it finds. Drive Space is a program that can compress files on a disk drive to save space. Disk Defragmenter is a program that rearranges the data on a disk drive to improve performance.
Doskey is a command-line interpreter that can be used to create macros and reassign keyboard shortcuts. It is not a system tool because it does not manage the computer's system resources.
