What should you do to prevent Spotlight from showing specific file types?

To prevent Spotlight from showing specific file types, the most effective action is to deselect categories under Spotlight preferences. This option allows users to customize the kind of content that Spotlight indexes and displays in its search results. By accessing the Spotlight preferences in System Preferences, you can select the categories that you want Spotlight to search for or exclude completely, which effectively manages what is shown in Spotlight searches.

Choosing to modify the file type in System Preferences does not directly control Spotlight's visibility of those files; rather, it affects how the operating system recognizes and interacts with the files. Removing files from your Mac entirely is not practical if you want to keep them but simply want to hide them from Spotlight searches. Changing the privacy settings of the specific file type is not a standard terminology used in macOS and does not align with the known functionalities pertaining to Spotlight preferences. Therefore, deselecting categories is the most straightforward and user-friendly approach to limit Spotlight's scope of indexed content.