The correct answer is C. To automatically retract malicious emails from the inboxes of impacted users. Proofpoint's product description for Threat Response Auto-Pull states that it automatically identifies and removes malicious emails from user inboxes after delivery when those messages are later determined to be unsafe. This is one of the defining functions of TRAP and is core to how Proofpoint reduces dwell time for email-based threats that initially evade blocking controls.

This is important because some attacks are not conclusively malicious at the exact moment of delivery. TAP and related analysis components can later determine that a delivered message is dangerous, and TRAP then enables remediation by pulling that message from affected mailboxes. The other options do not reflect the product's purpose. TRAP is not an end-user self-service spam-deletion tool, does not encrypt all internal email, and does not blanket-block all messages containing links. In the Threat Protection Administrator course, TAP and Threat Response topics emphasize post-delivery detection and remediation workflows, and TRAP is specifically the capability that automates message removal from inboxes once a threat is confirmed. Therefore, the correct answer is C.