What best describes a Certificate of Analysis provided by lubricant suppliers?

A Certificate of Analysis (CoA) provided by lubricant suppliers serves primarily to confirm the quality and specifications of the lubricant product. It is a document that typically includes details such as the physical and chemical properties of the lubricant, test results, and compliance with industry standards. This assurance of quality is essential for ensuring that the lubricant will perform effectively in its intended application, maintaining the integrity of machinery and prolonging its lifespan.

While other options may describe different types of documents or guidelines in various contexts, they do not accurately capture the primary function of a CoA. A legal document represents contractual obligations, a safety guideline focuses on health and safety practices, and an instruction manual provides usage instructions, none of which align with the key purpose of a Certificate of Analysis, which is to provide confidence in the product's quality.