Which resource could BEST help a CEO determine how to identify the category of CUI...

The best resource for identifying the category of Controlled Unclassified Information (CUI) is NARA , because NARA is the CUI Executive Agent for the federal CUI Program and maintains the authoritative CUI Registry . The Registry is specifically where the government publishes the approved CUI categories (and related markings and handling guidance) used across the Executive Branch.

NARA’s own CUI FAQs explicitly point users to the CUI Registry as the place that “lists all authorized CUI Categories (basic and specified).” Likewise, NIST’s CUI-related FAQ page also points to the NARA CUI Registry for CUI categories, reinforcing that the Registry is the correct source for determining which category applies to a given type of information.

By contrast, DFARS Part 252 (including clauses like 252.204-7012) addresses contractual safeguarding and cyber reporting requirements, not the authoritative categorization list itself. The CMMC Assessment Guide is about how to assess controls for CMMC levels, not how to determine CUI categories. And the Cyber AB (formerly CMMC-AB) administers the ecosystem and assessment processes, not the federal CUI category taxonomy. Therefore, NARA is the best answer.