Which system file is responsible for storing index references to both deleted and active files on a system?

The correct answer, index.dat, is responsible for storing index references to both deleted and active files on a system. This file is commonly associated with Windows operating systems and plays a crucial role in managing file references. Index.dat files are used not only for caching Internet Explorer history but also as part of the file system's data structure that keeps track of the locations of files, including those that may have been deleted. Thus, it enables the operating system to retrieve information about files that are no longer in an active state, alongside those that are currently accessible.

The other options do not fulfill this specific function. The info2 file, for example, is used by the Windows operating system to store information about deleted files in the Recycle Bin but is limited to that specific context. The catalog.dat file typically relates to the cataloging of various data and resources but does not specifically index deleted and active files like index.dat does. Lastly, the system32 directory is a critical Windows system folder that contains important system files, but it is not a specific file type responsible for indexing file references.