Which NTFS system file contains definitions for all system and user-defined attributes of the volume?

The file that contains definitions for all system and user-defined attributes of the NTFS volume is the $attrdef file. This file is integral to the NTFS file system as it provides critical information regarding how attributes associated with filesystem objects are interpreted and managed. When a new attribute is created, it is defined within this file, allowing the file system to maintain consistency and understanding of various attributes across the volume.

The $mft file, or Master File Table, is crucial as it contains metadata about every file and directory on the NTFS volume, but it does not specifically provide definitions of attributes. Instead, it utilizes the information contained within the $attrdef file to understand what those attributes mean.

The $data file refers to the actual content of files stored on the NTFS volume, while $standard_info is a system file that holds standard information about a file, such as timestamps and file attributes, but again, it does not encompass attribute definitions as the $attrdef file does. Thus, the uniqueness of the $attrdef file in providing definitions makes it the correct answer in this context.