Which statement about the hierarchy of codes, standards, and listings is accurate?

• A. Codes are consensus guidance; standards are legally adopted minimums; listings are untested.
• B. Listings are tested assemblies; codes are legally adopted minimums; standards are consensus guidance.
• C. Standards are tested assemblies; listings are legally adopted minimums; codes are consensus guidance.
• D. Codes are tested assemblies; standards are consensus guidance; listings are legally adopted minimums.

Answer: (B)

Understanding how listings, codes, and standards fit together helps explain why this statement is correct. Listings come from third‑party testing of a specific assembly or product; a testing laboratory evaluates the actual construction and performance and a listing is issued only after that assembly has been proven to meet the tested criteria. Codes are the legally adopted requirements that jurisdictions enforce; they set minimum safety and performance rules and are put into law through adoption by authorities having jurisdiction. Standards are established through consensus by recognized bodies; they provide agreed-upon methods, criteria, and practices but are not themselves enforceable unless a code or regulation adopts them or references them.

So the accurate description is that listings are tested assemblies, codes represent legally adopted minimums, and standards provide consensus guidance. The other statements mix up what is tested versus guidance versus enforceability, such as portraying listings as untested or standards as tested assemblies or codes as mere guidance.