Final answer:
A full backup would result in the largest storage space when compared to incremental, differential, or nightly backups as it copies all data in the system every time it's performed.
Step-by-step explanation:
The type of backup that would result in the largest storage space requirement is a full backup. A full backup creates a complete copy of all data on the system every time it is performed. This means it duplicates the same files multiple times if multiple full backups are completed over time, which leads to more storage consumption compared to other backup methods. In contrast, an incremental backup saves only the files that have changed since the last backup, which could be previous incremental or full backup, and typically requires less storage.
A differential backup stores all changes made since the last full backup but does not include the changes already backed up by previous differentials, making it larger than incremental backups but smaller than repeat full backups. Nightly backups can be either full, incremental or differential, depending on how they are configured, so the term 'nightly' itself does not indicate the storage size.