Which option correctly states the annual requirement for following manufacturer's test procedures?

• A. Optional
• B. Non-functional
• C. Conditional
• D. Functional

Answer: (D)

Annual adherence to the manufacturer's test procedures is a procedural requirement that directly governs how the product is validated each year. By following the prescribed test methods, you ensure the product still meets its intended function and tolerances, and you maintain measurement traceability and reliability of the results. This makes it a functional requirement—it specifies what must be done to ensure the product operates as intended.

It's not optional because the term annual implies a mandatory, recurring practice. It's not conditional because there’s no stated condition that would exempt the requirement in any given year. And it's not about a quality attribute of the product itself (like performance or reliability) but about the required process used to verify that the product meets specifications, which is why it falls under functional requirements.