In Avaya IX™ Messaging, the Synchronization Options tab of a Mailbox configuration allows administrators to set parameters related to voice verification features. This includes the ability to enroll mailboxes in voice verification and to configure the security levels associated with this feature. It ensures that the mailbox can be secured with an additional layer of protection, leveraging voice biometrics for authentication.

References: The answer is derived from the information available in the Avaya IX™ Messaging documentation and resources that discuss mailbox configurations and synchronization options1.