The correct answer is C. Deletes the listed attachments from the message and continues processing. In Proofpoint protection workflows, executable-attachment stripping rules are designed to remove risky attachment types while allowing the rest of the message to continue through the message-processing path. This aligns with the course-tested behavior of the default exestrip rule: it strips the prohibited executable attachment rather than deleting the entire message. Proofpoint's broader malware and attachment-protection references describe a layered approach where suspicious or dangerous attachments are inspected, sandboxed, blocked, or otherwise handled without assuming that the entire email must always be discarded.

That distinction matters operationally. If the rule deleted the whole message every time, the answer would be D, but that is not what this named default rule is testing in the course. It is specifically about stripping the attachment and continuing processing. The other options are also incorrect because the rule is not fundamentally a quarantine-notification rule and not a routing action into Message Defense. In the Virus Protection section of the course, administrators are expected to understand that some controls remove dangerous content from a message while preserving the message body and other safe parts for continued evaluation or delivery. Therefore, the verified and course-aligned answer is C.