According to IBM Instana Observability (v1.0.307 and earlier), stanctl cluster backup is a built-in utility and command-line tool to back up system state and operational data from an Instana cluster. The verified procedure reads: "stanctl cluster backup saves configuration, operational state, and selected monitoring data into an archive file located in the current working directory." This archive is designed for disaster recovery and migration, containing all crucial files needed for restoring Instana to a consistent state. Disk snapshots (A) are separate and handled by storage appliances. Option B describes pre-backup preparation rather than the actual result. Remote backup (C) operations require remote execution configuration and are not part of the default cluster backup. Thus, D is correct as per documentation, which emphasizes bringing together all cluster backup data in a portable .tar or .zip archive for safe storage or transfer.