Which of the following Windows Server 2003 technologies can help with making backups of open files?

Differential backup is a strategy for backing up changed files, but it does not inherently provide a mechanism for handling open or locked files during the backup process.

A snapshot is a generic term for a point-in-time copy, but VSS is the specific Windows Server 2003 technology that enables such snapshots for reliable backup of open files.

The Volume Shadow Copy Service (VSS) in Windows Server 2003 is designed to create consistent point-in-time copies (shadow copies) of volumes, including files that are currently open or locked by applications. This allows backup applications to access these shadow copies, ensuring data consistency even when files are in use.

Incremental backup is a strategy for backing up changed files since the last backup, but it does not address the challenge of backing up files that are actively in use or locked.