Which of the following file extensions is used for a consolidated group of files?

.bat is a batch file, which is a script file in MS-DOS, OS/2, and Microsoft Windows that contains a series of commands.

.avi is an Audio Video Interleave file, a multimedia container format for video and audio.

The .rar extension signifies a Roshal Archive Compressed file, which is a proprietary file format for data compression, error recovery, and file spanning. It is commonly used to group multiple files and folders into a single, often smaller, archive file.

.rtf is a Rich Text Format file, which is a document file format used for exchanging text and other content between different word processors and operating systems.