Your organization is in the midst of implementing a comprehensive Data Loss Prevention (DLP) strategy to safeguard sensitive information in the cloud. As the cloud security architect, you are tasked with ensuring that the DLP system operates effectively and aligns with the organization's data governance policies. Recognizing that DLP systems rely on certain foundational elements to function properly, you must identify a critical prerequisite that will enable the DLP system to detect and protect sensitive data accurately. What is this essential prerequisite, and why is it fundamental to the success of the DLP system?