Which of the following is the MOST important prerequisite for implementing a data loss prevention...

A data loss prevention (DLP) tool is a software application that detects and prevents data breaches by monitoring and protecting sensitive data from unauthorized access, transfer, or use1. A DLP tool can help your organization comply with regulations, prevent insider threats, and protect your intellectual property.

Before implementing a DLP tool, the most important prerequisite is to identify where existing data resides and establish a data classification matrix. This is because you need to know what data you have, where it is stored, how sensitive it is, and who can access it. A data classification matrix is a framework that defines the categories and levels of data sensitivity, such as public, internal, confidential, or restricted2. By identifying and classifying your data, you can determine the appropriate DLP policies and controls to apply to each type of data and prevent data loss or leakage.