Question: ______ is a unique tag, usually a number, identifies the file within the file system.

Answer:

From the given options, the correct choice for a unique tag that identifies the file within the file system is 1. File identifier. The file identifier, commonly known as the inode number, serves as a unique identifier for a file within a file system. It is assigned to each file's corresponding inode and is used by the operating system to locate and manage the file's data. The file name and file type, on the other hand, are attributes associated with the file but do not necessarily provide a unique identification within the file system.