Refer to the exhibit.

The XML (STIX/CybOX format) details anemail-based threatindicator. Specifically:

Theemail addresscontains “@state.gov” (not exact match, so blocking all @state.gov would be overbroad).

Theattachment is a PDFfile with a specifiedMD5 hash: cf2b3ad32a8a4cfb05e9dfc45875bd70.

Theattachment sizeis 87022 bytes.

From a threat mitigation perspective:

Ais correct: Updating AV to block or flag files matching the malicious hash is a standard response.

Dis correct: The email address context and hash together provide a precise rule for blocking—this prevents false positives.

Incorrect options:

Boverreaches by blocking an entire domain without confirming threat context.

Cwould stop all PDFs, which is impractical.

Eis incorrect; there is no indication that the hash appears in the subject line.