Explanation:

The correct answer is (d) full. A full backup is a comprehensive backup method where a complete copy of all selected data, including every program, data file, and system file on a computer or server, is made at a specific point in time. This type of backup is self-contained and can be used to restore the entire system or specific files to the state they were in when the backup was performed. While it consumes more storage space and takes longer to create than other backup types, it offers the simplest and fastest restoration process. (a) Restoration is the process of recovering data from a backup. It is an action performed *with* a backup, not a type of backup itself. (b) Bootstrap, or bootstrapping, refers to the process of starting up a computer system from an initial state, or a self-sustaining process that proceeds without external input. It is unrelated to backup types. (c) A differential backup copies all data that has changed since the *last full backup*. It does not copy *every* program, data, and system file each time, only the accumulated changes since the most recent full backup. This requires both the last full backup and the latest differential backup for a full restoration. (e) None of these is incorrect, as option (d) accurately describes the type of backup that copies everything.