Which of the following file extension names indicates a "system" file extension?

To determine which file extension indicates a "system" file, it's important to look at common file extensions associated with system files. System files are typically used by the operating system and include critical components for it to function properly.

Common extensions that indicate system files include:

1. .sys - This is a primary extension for system files in Windows operating systems, typically containing device driver files.
2. .dll - Dynamic Link Library files are used by the operating system to run applications and perform specific tasks.
3. .exe - Although executable files can be application-related, many system components are also in the form of executables.

In general, among the various file extensions, .sys is a definitive indicator of a system file. Always ensure to cross-check with context, as some extensions can serve multiple purposes depending on the software or system in question.