The correct answer is MS-DOS.A Single-User Single-Tasking Operating System is an operating system that allows a single user to complete only one task at a time.Printing a paper, downloading photographs, and other tasks can only be done one at a time.MS-DOS and Palm OS are examples of the single-user operating system.MS-DOS (Microsoft Disk Operating System) is an operating system for x86-based personal computers mostly developed by Microsoft. This operating system is commonly seen in wireless phones and two-way messaging devices.It takes up less memory space.It can only handle one task at a time.A single user operating system allows a single user to access your computer at a time, although it can also support numerous profiles in specific cases.Additional InformationSingle-User Multitasking Operating System is an operating system that allows a single user to execute multiple tasks at once.Microsoft Windows and Macintosh OS are two examples.Unix is a multitasking, multiuser computer operating system developed by Ken Thompson and Dennis Ritchie.Xenix is a discontinued version of the Unix operating system licensed by Microsoft.