A user has a computer with a single SSD, and the entire drive contains one partition. The user wants to install a second OS on the computer without having to reinstall the current OS. The user wants to be able to select which OS to use when booting the computer. Which Disk Management tools should the user utilize to accomplish this task?

The correct approach is "Shrink partition". A further explanation is given below.

Explanation:

Shrinking partition shrinks or decreases this same disc size as well as unallotted disc space, unallotted space could be utilized to mount a secondary Operating system to operate as a double operating system.Whilst also diminishing everything into neighboring volatile memory on another disc, this same space required for area as well as drives could also be reduced.

Thus the above is the correct answer.

I’m not really much sure, I tried.