An engineer needs to migrate users from a Windows-based Unity system to Cisco Unity Connection. Which tool must be used?

LDAP is used for directory synchronization and importing user accounts from a directory service, not for migrating voicemail data between Unity systems.

BAT (Bulk Administration Tool) is used for bulk provisioning of endpoints and users within Cisco Unified Communications Manager, not for migrating Unity voicemail platform data.

AXL (Administrative XML Layer) is a SOAP-based API for programmatic provisioning of CUCM objects, not a migration utility for Unity or Unity Connection data.

COBRAS (Cisco Object Backup and Restore Application Suite) is specifically designed to back up subscriber data, greetings, and messages from Cisco Unity and restore them into Cisco Unity Connection, making it the only supported migration tool for this scenario. It handles the object-level data translation required between the two different platforms.