A company's legal and regulatory departments have drafted a new policy in which emails must be retained for no longer than three years. Which of the following locations should an administrator…

Local workstations frequently store email data in local archive files such as PST files, and these copies must be subject to the same three-year retention limit to ensure full policy compliance.

Backup tapes contain copies of email data that persist beyond normal deletion cycles, so they must be configured to purge or expire records older than three years to avoid retaining data in violation of the policy.

Domain controllers store Active Directory objects and authentication data, not email messages, so they are not a relevant target for an email retention policy.

The email server is the primary repository for all organizational mail and is the most critical location to configure with retention rules, ensuring messages are automatically removed after the three-year limit is reached.

SMTP gateways relay mail in transit but do not function as long-term email storage repositories, making them irrelevant to a retention compliance configuration.

Proxy servers handle HTTP/HTTPS web traffic and do not store or process email data, so they fall outside the scope of an email retention policy.